Overheating or random shutdown?

Last night I while I was using my iMac it randomly shutdown twice, one right after another.
I have had the random shutdown problem in the past but have not experienced one for quite some time. (I had taken several steps to fix, including running the disk utilities and deleting some power management file. Whatever I did seemed to be working.)
I had also been using iMovie, exporting movies, all day. I had also been heavily using iPhoto and Firefox, moving photos out and onto Facebook. The case was hot to the touch and iStatpro said that the power supply was around 159 degrees F and the CPU was around 135 degrees F. Is it possible I triggered some sort of safety cutoff?
Please help me out here. I love this computer but the random shutdowns are totally killing it. Thanks in advance.

Hello All,
Here's my experience with unexpected shutdowns...
My 20" Intel iMac is 6 months old - August 08.
- After shutting it down one evening as per normal, it just wouldn't turn on the next morning. Nothing I did worked: different power socket, changed the fuse (UK plug) etc. When I had just about given up carrying it around the house, it suddenly came back to life. Went to the shop to buy milk, got back and off it was again. Weird. So I spoke to Apple Care who suggested I take it down to the Apple Store in central London, UK. I laboriously did so (try taking the underground with an iMac... not fun) and dropped it off mid afternoon.
- Got a call the same evening from Apple Store: my iMac turned on fine first time (typical), tests were being run on it (basically stress testing the processor with multiple processes), and it was fine. No fault was found, I could go and pick it up.
- So I take it back home the next day, again battling with London commuters with my heavy, bulky iMac box and plug it in. All fine. Work all day on it as per normal (nothing intensive). Then at about 10pm, it just turns off. No warning, nothing. Just off, and this time its staying off. I let it cool down, nothing. Diffent plugs, nothing. Change the plug fuse, nothing. Next morning, nothing. Its dead.
- So I head off directly to the Apple Store again, iMac in hand, and battle it out again with London commuters on the underground. I explain the situation, am promised this will be a priority repair...
- Eventually, after 10 days (Christmas got in the way), I get a call that it is ready. Two items of hardware were changed, namely 1) power supply and 2) Cable/DC Power/SATA/Inverter. Though none of them were actually faulty, they are the items that can cause sudden shutdowns...
- I pick it up, and it seems fine since. But upon switching it on, I noticed the whole bottom half of my dispay was dim. Bright at the top, grey at the bottom... Another chat with Apple Care (by then am on first name terms with the whole team), we do various hardware resets to no avail. Am advised to drop it off at Apple. So off I go to the Apple Store again.
And I just got it back again.. with a new LCD display...
(http://discussions.apple.com/thread.jspa?threadID=1730239&tstart=0)
So the cost of all repairs to my 6 months old iMac is now more than half of the overall cost of the machine. Still, credit to Apple for not quibbling on any of the above issues, and fixing them (relatively) quickly and efficiently.
Now lets hope my iMac stays on and stays bright...

Similar Messages

Heatsink Thermal Paste Random Shutdown Revelation

Symptom: Random freezes, overheating problems, random shutdowns if pressure not applied to top or bottom of computer
Solution: Make sure screws are tight!!
Model: Mid 2007, pre-Unibody
Screws: The two torx screws under the memory panel
I've been doing TONS of searching to try and solve a problem with my macbook pro freezing, even at low temperature. I have seen many people that have had VERY similar symptoms as me, and would constantly discuss having to re-apply thermal grease. I have only applied thermal grease once (arctic silver) and was having these problems. As I disassembled it today getting ready to reapply it, I pondered carefully while taking apart my macbook for the billionth time. I thought about the points in which I had to apply pressure in order for my macbook to power on properly and not freeze. When I got to the torx screws, I realized these were responsible for clamping the logic board to the bottom case. It is most likely quite important that they be properly tightened, as these are basically the heatsink-processor mating screws!! There should probably be a torque rating for these, as I would be afraid of tightening them too much and breaking the plastic they screw into. Also, I would alternate back and forth between them.
I had recently transferred my logic board from my MBP to a used one I purchased which has the defective logic board (I plan to bake some time in the future). There were many reasons I purchased the additional MBP, but it was mostly due to mine being in really bad physical condition (dropped, marked up, material loss on upper case at palm area), having a bad display (I bought a replacement but spilt liquid on it) (also had the keyboard/trackpad disconnect issue, but I frankensteined the connector, which I had broke as well, to ultimately work perfectly again). I had THOUGHT I had another problem with the issues in the subject of this post. I was taking apart my original MBP a lot for my display replacement, as well as memory and hard drive upgrades. That's when I first started getting issues with strange freezes and shutdowns. I believe that this lack of tightening of torx screws was the problem even when my logic board was in my original case. The problem definitely became a lot more frequent when I transferred it to the new/used case and in the process cleaned and re-greased the processors. I had trained myself to not tighten those screws enough, and this was especially bad when the new thermal paste needed to be squished down.
This has been quite a frustrating issue to deal with for the past 6 months or so. A year ago I purchased a brand new adapter and battery from Apple, and I was fearing that they had gone bad (I have the fraying at the magsafe connector....should have taken better care of it, but it can be repaired). Luckily the only loss from this whole dilemma has been a lot of time and a couple hundred to purchase a 2nd machine used, which was actually a great buy. Hopefully I'll bake the bad logic board and get the 2nd machine up and running some day, at the very least it's spare parts! It is great to have the perfect condition LCD and nice condition case.

Alright, so I got to the point where I was having the problem nice and consistently. It happened to be when my battery was low on charge (I believe this can happen with a high charge too though...). I experimented with having the battery in and out and was able to reproduce the problem even with the battery removed.
When I was repeating the shutdown failure (it would happen exactly this way when my computer would freeze during normal or non-use <randomly> and would try to turn it back on) I could turn it on if I was tilting the comp, then I would tilt it back toward resting and it would shut off. I did this with the battery in and out, so I could at least rule the battery out. I then started playing with the top case a bit. I noticed the more I had it removed, the more often it seemed to turn on. I found that bringing the top case down would trigger the shutdown.
There seems to be some sort of grounding issue. I honestly have never been super careful with pads and tape, so missing one of those might be the cause.

Random shutdown issues, battery, and overheating.

Hi,
About two weeks ago, I've experienced random shutdowns on my MacBook Pro (Bought it on October).
I am not sure if all this problem was about battery issues. First I've charged it for the first time and only lasted 1 hour. then I recalibrated it and now it last 2 hours and a bit more.
Now, apart from having battery issue, I've experienced random shutdowns from my laptop. I had installed all the available updates for my laptop.
Reading all the posted topics about heat, shutdowns and batteries, maybe my problem is just overheating.
So I've installed the fan control, adjusted the speed to 3500 rpm and worked fine.
But one thing came to my mind:
Is it safe for the fans to actually force the speed all time? if so, their cycle life could be shorter?.
On either case, what if the MBP actually has a defective factory error and if I still be using it, it could completely "melt from the inside"?
Does the battery itself has something to do with the overheating itself?
Maybe I should call for a laptop replacement as well.
Any suggestions?

Your Mac will very likely last as long as you own it or otherwise choose to upgrade. The heat issues posted here are not entirely valid. With that said, you might want to verify that your battery isn’t on the recall list by viewing the link provided below.
Excerpt:
"The affected batteries have model number A1175 and a 12-digit serial number that ends with U7SA, U7SB or U7SC. To view the model and serial numbers located on the bottom of the battery, you must remove the battery from the computer. The battery serial number is located above the barcode. See photos below. Only batteries within the noted serial number ranges need to be exchanged."
https://support.apple.com/macbookpro15/batteryexchange/
Regards,
 MBP-15"/2.16/2GB RAM/7200/W8612... Mac OS X (10.4.8) G4 Tower (OS 9/10), Dell 620 WorkStation (XP Pro), Gateway P4 (XP Home)

K9N Platinum: CPU upgrade = Random shutdowns..

I just installed a new AMD Athlon 64 X2 3800+ EE in my MSI K9N Platinum motherboard (MS-7250 v1.0, the 070 model according to the box). I had updated the BIOS to version 1.7 before installing the CPU. Anyhow, I got the CPU installed and it seemed to be running fine. Until I started playing my games. Upon playing fifteen (!!!) minutes of Day of Defeat, the system completely turned off. COMPLETELY. No error messages. I check core temp's log to make sure the CPU wasnt overheating; it wasnt. The max temp was 38C on one of the cores. Just to make sure the CPU wasnt the problem, I ran two instances of prime95 for 5 hours and there were no calculation errors whatsoever. I also ran 3-4 loops of SuperPi, using the 32M test. No errors.
I have come to the conclusion that it must be the motherboard, and possibly it does not like the CPU. Or else it is having the same random shutdown problems as many other K9N Platinum/Ultra boards are experiencing. From what i have read, this issue only relates to boards that are 040, 050, or 060 models. I have a 070 model, and I AM GETTING THIS PROBLEM!!
Help!!!
Full specs:
MSI K9N Platinum MS7250 V1.0, BIOS 1.7, model 070
AMD Athlon 64 X2 3800+ EE (old CPU: AMD Athlon 64 3500+; had no issues with the 3500+) vcore: 1.225
1 GB OCZ Platinum DDR2-800, 5-5-5-15, 2.1v
eVGA GeForce 7800GT videocard with Zalman VF900, 490/1220
Hitachi Deskstar 7K80 SATA HDD
LITE-ON DVD-ROM drive
Floppy drive
3x 80mm fans, 1 cold cathode
Antec Truepower 430 watt PSU, dual +12v @ 17A a piece.
Any ideas?

well, i know that ACPI has to do with power saving features.
http://en.wikipedia.org/wiki/ACPI
and HPET also has something to do with CPUs
http://en.wikipedia.org/wiki/HPET
and MCP55 is the nortbridge.
so i suppose i can conclude that it protects from overvoltage or promotes more power-saving? i dunno i really dont care as long as my PC works now,

Random Shutdown Because of Heat Sensors?

I bought my white MacBook in mid-May (week 19 production) and it worked fine with the exception of a whine when I did not have the iSight Cam on, the occasional mooing after using the computer heavily then using the CPU lightly for a while, and the discoloration. If you ask me it wasn't that much of a set back because this computer was fast and reliable... or so I had thought!
All of a sudden about a week ago, after I had the discoloration fixed, thanks to AppleCare (which only took 5 days), my computer shut down randomly in the middle of light usage...
At first I had thought that my external hard drive was the problem and I was very upset that this had happened. I tried to reboot my computer, but all that would happen was the usual DVD drive start up sound and then it would turn off again. I tried about 5 times to restart it with no luck, so I walked away. About 20 minutes later I was able to start it back up...
After not using my external hard drive for a day, it happened again, in the middle of normal internet browsing and listening to music it randomly shutdown. I thought that maybe it was an OS 10.4.7 issue, because I had not had any problems with x.6, so I erased and restarted from scratch, and once again, another MacDeath. Once again, I thought it to be my fault in my installation of 2Gb of RAM. I re-installed the custom 2x256 RAM that came with the computer ( and will remain in my hands forever, because you can't even pay someone to take away a stick of 256Mb RAM these days) well after the old RAM was forcefully shoved back in, it died again! This is when I started to get mad...
I put up with the whinning, I put up with the heat, I put up with the discoloration (for a while), but now this? WHY!
Over the next week it happened almost daily and sometimes when I would turn on my computer after it being off for at least 5 hours, it would load my home screen and after about a minute I would hear the fan come on for a few seconds, and then it would die again. I noticed that most times that my MacBook would shutdown unexpectedly, the fan had just turned on for a few seconds or I was playing a game and the fan was already on...
So today I called AppleCare and I had to wait about 30 minutes before I talked to someone... (When I called last time about discoloration, the wait was about 5 minutes) So either there are more and more angry customers calling, or Apple is firing employees to increase their stock value...?
When I finally got through the man told me that it was most likely not the Logic Board, but instead FAULTY HEAT SENSORS and/or FAULTY HEAT SINK APPLICATION. I won't lie I have seen Core Duo Temp show readings as high as 91 C (about 196 degrees F). I knew that this things got hot, but not so hot as to start a fire if left on too long....
So I am getting a box from DHL tomorrow (woohoo) MacB. and I get to part ways again, but this time, from reading many threads, I assume our time apart will be much longer approaching around 2 WEEKS!!!
All I hope is that AppleCare will fix the heat sensors that are supposed to shutdown the computer when it gets overheated.... I have to go to school in about a month and I will not have time to deal with these kinds of issues! I really like the MacBook and all of it's features, but I did not sign up to get a MacDieOnMeBook!
APPLE USE SOME OF THE 24% SALE INCREASE THIS QUARTER TO HELP YOUR LOYAL CUSTOMERS WHO HAVE BEEN WITH YOU THROUGH THE GOOD AND THE BAD!
MB 2GHz White 2GB RAM - 250 GB External HD Mac OS X (10.4.6)

As of yet i'm not exactly sure about the heatsink problem, although a few in here have reported machines that work well after having this part replaced, while others who only had the MLB replaced reported a recurrence of the problem.
as for the volume indicator, i noticed that mine did that too, but it was in fact muted whether or not the tool bar indicated it. i dismissed this as a small quirk, similar to when my volume indicator didnt change as i pressed the volume buttons on my old laptop. but so long as there was an acknowledging "squirt" noise on the computer indicating change of volume, that shouldnt be a problem.
good luck withyour MB

[solved?] possible reasons for random shutdowns

Several months ago, my laptop started to suddenly shutdown for no apparent reason. Initially, I assumed it was overheating. Lenovo had a look, found nothing but replaced the thermal paste anyway, gave it back.
The issue continued so somebody from IT stuck my laptop in a server room on top of a hot computer and stress tested it for a few hours. Conclusion: can find nothing wrong, definitely not a heat problem! (Laptop never went above 65.) They ran a bunch of hardware tests as part of this, got my cable and adaptor tested etc.
Next theory: issue had only ever occurred on one level of the building (in my office) and it turned out there had been another issue with another laptop in that area and it turned out to be shutting down to protect itself due to spikes in the power supply. A UPS solved that issue. One is currently on order for me.
Meanwhile, last weekend I had the issue occur twice in a friend's house in Birmingham. Even more worrying, however, I just had it happen here at home even though I use the machine extensively here and have never seen this happen here before.
I'm guessing this rules out the environmental hypothesis although I'm by no means certain of this.
That leaves: hardware or software.
Hardware is a pain - Lenovo already ran it for 48 hours straight and found nothing. Moreover, although I have paid to extend the warranty and although they've taken my money, I've so far been entirely unsuccessful in getting Lenovo's system to recognise the extension. In any case, with the holidays and everything I'd rather be sure of what I'm dealing with before giving the machine up for an extended period of time. I cannot reliably reproduce the issue so it is hard to troubleshoot.
So I would like to know what possible software issues might trigger apparently random shutdowns.
The shutdowns are immediate. One minute I am working on some document or whatever. The next the machine is off. journalctl shows nothing except:
-- Reboot --
If it was a hardware protection feature, would this get logged?
It does not reboot - it powers off - but I always have issues with reboot since I switched to systemd. Generally, it just powers off instead. [Oh, and before anybody tries to blame systemd, the random shutdowns started before I switched to systemd.]
I've checked the RAM.
Any suggestions, however unlikely, are welcome at this point.
Last edited by cfr (2013-04-13 23:42:03)

Thanks. The adaptor, cable etc. was "PAT tested" by the electricals person in our building and they checked the fuse etc. in the plug as well. Moreover, the laptop never usually has a problem switching from AC to battery and back. My battery is more than adequate for this sort of purpose and, if the battery did run low, the laptop would automatically suspend to RAM. Also, I know if this happens because, among other things, the display is set to dim on switch to battery. When the power supply has disappeared due to a power cut or just unplugging it, the switch has always been flawless.
I've just been jiggling and shaking and rotating the laptop itself as suggested above with no effect whatsoever. I've also tried pressing around the edges of the casing just in case I'm somehow putting pressure somewhere and that's affecting things. (I assume if it was pressure due to typing or touchpad, it would be happening all the time.)
I've also just spent a while jiggling the adaptor and both parts of the cable - also with no effect.
The one thing which makes me reluctant to test sans battery is that I've read that the batteries in ThinkPads serve some sort of protective function in case of issues with the power supply and that you shouldn't use them without the battery for that reason. (Somewhere on Lenovo's site but it was months ago so I can't remember where to check the details.) In case there is an issue with the power, I'd obviously rather not fry the laptop. (But it seems weird if it happens in several places in that case...)
I'm not sure about the cold boot comment. Do you think a cold boot might help? If so, I already performed one yesterday as I opened the back to look for loose connections. So if a cold boot might help, I'll just have to see. I've done cold boots before, though, after opening it up to look for issues following shutdowns.
These issues appeared several months ago and I've reproduced the issue with the LTS kernel a while back. So if it is a regression, it has been around for a bit. I might try a live Ubuntu USB. (I don't have an optical drive.) The problem is that a negative result won't really prove anything because the issue is so random. Given that yesterday is the first time it has ever happened to me at home and that even in my office I've sometimes gone three or four days without problem, a couple of days testing won't cut it. (And will make it difficult for me to get stuff done!) It might be best to wait and try it in my office after the holidays - if it worked for, say, a week there without issue, that would strongly suggest something in my Arch setup. (Or something about the hdd, I guess.)
Somebody suggested modules so, for the record, here's output from lsmod:
Module Size Used by
usb_storage 47385 0
uas 11120 0
efivars 12441 1
fuse 69213 3
hid_generic 1114 0
usbhid 37036 0
hid 85974 2 hid_generic,usbhid
rfcomm 33792 8
bnep 8858 2
ipt_REJECT 2282 2
ip6t_REJECT 2797 2
xt_LOG 12055 6
xt_limit 1978 6
xt_tcpudp 2472 4
nf_conntrack_ipv4 7799 5
nf_defrag_ipv4 1340 1 nf_conntrack_ipv4
nf_conntrack_ipv6 7512 5
nf_defrag_ipv6 6318 1 nf_conntrack_ipv6
xt_recent 8603 12
xt_conntrack 3298 10
nf_conntrack 64101 3 xt_conntrack,nf_conntrack_ipv4,nf_conntrack_ipv6
iptable_filter 1457 1
ip_tables 16947 1 iptable_filter
ip6table_filter 1397 1
ip6_tables 18519 1 ip6table_filter
x_tables 17000 11 ip6table_filter,xt_recent,ip_tables,xt_tcpudp,xt_limit,xt_conntrack,xt_LOG,iptable_filter,ipt_REJECT,ip6_tables,ip6t_REJECT
nls_cp437 5954 1
vfat 10120 1
fat 48403 1 vfat
uvcvideo 72788 0
videobuf2_vmalloc 2469 1 uvcvideo
videobuf2_memops 2283 1 videobuf2_vmalloc
coretemp 6071 0
kvm_intel 124718 0
snd_hda_codec_hdmi 24529 1
videobuf2_core 24073 1 uvcvideo
videodev 100860 2 uvcvideo,videobuf2_core
snd_hda_codec_conexant 47159 1
btusb 12373 0
kvm 374014 1 kvm_intel
media 10406 2 uvcvideo,videodev
joydev 9992 0
arc4 2040 2
bluetooth 192234 22 bnep,btusb,rfcomm
iwldvm 171052 0
mac80211 426350 1 iwldvm
snd_hda_intel 26181 2
snd_hda_codec 98034 3 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel
thinkpad_acpi 62562 0
snd_hwdep 6429 1 snd_hda_codec
snd_pcm 75735 3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
snd_page_alloc 7218 2 snd_pcm,snd_hda_intel
microcode 12346 0
snd_timer 18935 1 snd_pcm
nvram 5907 1 thinkpad_acpi
snd 60189 12 snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_pcm,snd_hda_codec,snd_hda_intel,thinkpad_acpi
rts_pstor 401665 0
atl1c 33647 0
psmouse 71952 0
iwlwifi 125182 1 iwldvm
iTCO_wdt 5256 0
iTCO_vendor_support 1930 1 iTCO_wdt
cfg80211 177109 3 iwlwifi,mac80211,iwldvm
rfkill 15605 5 cfg80211,thinkpad_acpi,bluetooth
soundcore 5443 1 snd
i2c_i801 9572 0
evdev 10267 25
serio_raw 4690 0
pcspkr 1900 0
mei 32666 0
lpc_ich 10610 0
ac 2537 0
thermal 8120 0
battery 6774 0
wmi 8380 0
nfs 127008 0
lockd 64905 1 nfs
sunrpc 186134 2 nfs,lockd
fscache 40996 1 nfs
acpi_cpufreq 5934 0
mperf 1300 1 acpi_cpufreq
processor 26856 1 acpi_cpufreq
ext4 440435 10
crc16 1360 2 ext4,bluetooth
jbd2 78802 1 ext4
mbcache 6027 1 ext4
sha256_generic 10262 2
ablk_helper 1973 0
aes_x86_64 7556 5
aes_generic 26139 1 aes_x86_64
cbc 2737 1
dm_crypt 15800 1
dm_mod 72106 35 dm_crypt
sd_mod 29560 4
crc32c_intel 1988 0
ghash_clmulni_intel 4278 0
cryptd 8742 2 ghash_clmulni_intel,ablk_helper
ahci 21361 3
libahci 20024 1 ahci
libata 167757 2 ahci,libahci
scsi_mod 133434 5 uas,usb_storage,libata,rts_pstor,sd_mod
ehci_hcd 41817 0
usbcore 150472 6 uas,btusb,uvcvideo,usb_storage,ehci_hcd,usbhid
usb_common 955 1 usbcore
i915 496012 3
video 11277 1 i915
button 4663 1 i915
i2c_algo_bit 5392 1 i915
intel_agp 10745 1 i915
intel_gtt 15660 2 i915,intel_agp
drm_kms_helper 32878 1 i915
drm 218903 4 i915,drm_kms_helper
i2c_core 20708 6 drm,i915,i2c_i801,drm_kms_helper,i2c_algo_bit,videodev
I did wonder about the watchdogs and whether I should try turning (any of?) them off. But I suspect this thought just shows my ignorance of these things.
I don't think there's a fan in my power supply - it is just a brick type adaptor between the AC and the laptop. If it is the battery, it would be odd that it only ever happens when I'm plugged into AC. (Again, I use it a lot more on AC and the problem is random so this need not mean much.) One difference between battery and AC is that laptop-mode tools is configured to disable the NMI watchdog on battery. But again, I don't understand enough of what this means to know whether this is even vaguely relevant.
My graphics is intel so I'm not using any closed source drivers from Nvidia or ATI. The driver is currently set to use the default acceleration. QT is using default rendering (X11/XRender) rather than Raster or the experimental OpenGL.

2006 model Random Shutdown

Here's some of the details:
My computer was purchased in May 2006. Since then it has crashed twice because of overheating. The power cord has been replaced, CPU fans and the HD x2. I have never had any problems with random shut down except 3 years ago it would shut down immediately after the power cord was disconnected.
A few days ago I noticed that whenever I returned from classes the computer would be shut off. The problem: I never shut it down.
I'm unsure if this is somehow connected or not, but a few years ago the cd burner suddenly quit working and then today I tried uncessfully to eject a dvd. It made the sound to eject, even began to eject the dvd but didn't make it out even 1cm before the computer decided jk, and stole it back.
Now the unit is shutting down while I only have firefox running. I restarted the computer and now the light on the power supply is absent, along with the battery % which is normally present.
I know it's 4 years old but nothing quite like this has happened before.
Also, when the unit shuts down, it is not even remotely hot. I've read several places that the heat sink expands (or maybe it was something else) which then causes a short circuit.
Does anyone have any ideas?

Do you have all of your firmware updates installed? A firmware update is a little different than a regular update. You would get the firmware update via Software Update, but you would have to manually install it after it downloads... going through a process involving holding down the power button when you start it up... and getting some loud beeps. Have you ever done that?
There was a known problem with random shutdowns in those machines related to a faulty heat sensor... the update was basically to ignore the faulty sensor.

GT780DX - Random Shutdowns

Hey. I've had a gt780dx for a good four/five months now, but last wednesday it randomly shut down. This has happened on various random points since then. Sometimes it's while starting up, sometimes it's just after it finished starting. Sometimes it's after two hours. Sometimes it doesn't happen for a day. When it does happen, it happens multiple times in a row.
I system restored my laptop on friday to a point before a windows update was installed on wednesday. It worked perfectly fine for the rest of the weekend after that, but it's happening again. Just now I noticed windows tried to sneak by an update again, even without my consent. I system restored, but it happened a couple of times again already. After each of those times it did display the 'system restore succesfull' message, though. And it seems fine now, but for how long.
It gives no error message or bsod before shutting down. Everytime I start it afterwards it tells me windows did not shut down properly and if I wanted to start in safe mode or not.
I have tried safe mode. It still happens during that.
I've just gone through the event log, and the one 'critical' error that pops up a lot is kernel power. Is this simply the name for a random shutdown or is this a clear sign that something in my laptop is broken?

It happens when it's plugged in and it's happened when I'm on battery. I can't imagine it's overheating problems as my computer has never really felt warm whatsoever. The only time it does get warmer is when I'm playing some games and it hasn't crashed during one yet.

2008 Macpro random shutdowns

I have a Mac Pro 2008 and it was the best computer ever.
Lately about 2 months ago it started to randomly shutdown.
The computer would crash with no indication, the screen goes
to black and after about 10 seconds, the fan would run at full speed.
All the while the power never cuts off.
what is going on ?
any experience ?
Help is much appreciated as I can't get any work going on at this time.

Start by cleaning out all the accumulated dust.
Do a smc and pram reset.
Boot from your recovery partition and repair/verify your drives (not repair permissions).
You might want to add a temperature monitor like iStat Pro, iStat Menus, Temperature Monitor, Hardware Monitor, etc. Maybe somthing is overheating.
Consider reseating your video card and dimms.

Random Shutdown Problem Fixed (for now)

I experienced the same random shutdown problems/symptoms with my MacBook that have been extensively described in this forum and elsewhere. I sent it back for repair under AppleCare and it was returned in 3 days. It has been running now for 4 days with no problems and far cooler and quieter (the fan rarely comes on) than it was before. The repair sheet indicates that the heat sink and heat assembly unit were replaced.
I'll keep my fingers crossed, but at least in my case and perhaps others, the problem may simply have to do with the thermal contact with the heat sink going bad and the processor simply shuts down due to overheating.
MacBook 2 GHz Mac OS X (10.4.7)

Followup:
They told me something interesting at my Mac Retailer. They have had two other machines brought in doing the same thing. They tried new logic boards with no success, they tried new thermal assemblies with no luck, new ram - nothing seemed to solve the problem.
What they finnally did was replace the Hard Drive - they tell me this has fixed the problem. Now I don't know if that is what they'll do to mine. The other two machines had the 60gb drives - mine is a 100gb, but we'll see. From all I have heard, this doesn't make a lot of sense to me. Anyway, we'll see what happens.
Anyone else hear anything about replacing the hard drive?
Clayton

Random Shutdown - Mac Mini

I was on my Mini last night, only 3-4 months old, practically new and it simply shut down. Screen went black, light went out and I have not since been able to get it turned back on. I have read a few instances of random shutdown from this board, but none of them seem to be my exact problem because everyone else was able to resolve their problem by plugging and unplugging and simple waiting. I, the next day, am still not able to use my computer. I just got back from being away for two days, the computer was shut off so I don't believe it to be an overheating issue. Could it be a faulty power cable? I welcome any thoughts. Thank you.

Welcome, Nash2785!
Since your mini is only 3-4 months old, if you are anywhere near an Apple Store, I'd suggest taking the Mini and power supply in and having the Genius Bar take a look at it. It is covered by a 1-year warranty.

Random shutdowns since battey update!

Hi.
I've had whine issues with my MBP 1st gen. which were fixed by a logic board replacement. I updated with the battery update recently and some bad bahaviour has happened since.
Namely I've had two random shutdowns which never happened before.
The first occasion I dismissed since I had it on high processor load and when the MBP shutdown I put it down to overheating.
Today the story was different.
The MBP was idling with some normal tasks. I unplugged the machine to cycle the battery as I do once a week or so. I calibrated formally last week after the battery update.
Approximately a minute after unplugging, the MBP activated both its fans to high speed. The processor load on both cores was under 10% so it was not due to processor load or rogue non responding process. I waited and the fans started to wind down from their high speed in the gradual way they normally do.
A minute or so later for no apparent reason the machine just shutdown all of a sudden.
The battery appears to be draining alot quicker. For example in the last ten minutes since I've been slowly typing this the battery % has gone from 90% to 75% with CPU loads under 10%.
I'm calibrating the battery again today but the sudden shutdowns really shake one's confidence in the machine in a deep way as you may all understand.

Did you Reset the PMU (power management unit)
between re-calibrations?
When you re-calibrate make sure you leave it more
than 5 hours draining without power, I generally aim
for 7 hours before re-connecting power.
It could be worth running the Hardware tests from
Install DVD1 (hold down d at boot) and see if it
reports any SNS (sensor) or MTR (motor) problems.
I calibrated formally ie. 6 hours after normal power related shutdown and wake from deep sleep mode.
I haven't reset the PMU but will try that later. I want to try and diagnose the problem as well as possible before trying lots of random things.
I have noticed that my battery is down to 90% of full capacity ie ~4900 mAh (5500 mAh is the nominal when new). I only have 122 cycles in the 14 months I have owned this. It's mostly on AC power but nevertheless it never occured prior to the battery update (Ockham's razor).

Macbook problems, hard drive crash, random shutdown, freezes

I bought my macbook used a few months ago, and it worked flawlessly until about 3 weeks ago. The system started freezing and not booting (getting folder icon instead of apple at startup). I ran drive setup and tried to repair the drive, but this did not fix the problem. DiskWarrior also could not fix it. I pulled the drive and installed a new hard drive, as I wanted a larger capacity anyways. All my problems appeared fixed for about two weeks, then similar problems began occurring. I backed up all the files I needed to an external firewire drive and attempted to reformat the new internal drive. Drive Setup says it can not reformat the drive - can't mount it and if it does, the drive disappears while in the process of formatting. I pulled the new drive and am having it replaced under warranty. I am using the firewire drive to run my computer, and this seemed to work fine for a day or two until the computer just started shutting down with no warning. Everything goes black, including the little light on the front of the computer. I have to hold down the power button for 10 seconds before it lets me start the computer back up. I had read this may be a memory issue, so I ran memtest and it says the memory is fine (I need to do it in single user mode still, however). I also tried pulling both sticks of ram. They are both 1GB crucial memory. I put each stick in by itself and tried it in both slots and was able to reproduce the shutdown issue with any ram configuration of either stick.
After all this, I realized the firewire drive was only running 10.5, so I updated all the software through software update, and it is now running 10.5.2. It seems to be working better as I have not experienced a random shutdown yet, but I'm anticipating it may start back up soon. Today, however I experienced a different problem - the screen froze on me and the only way to get anything to happen was to force a shutdown with them power button. It's restarted and seems to be working fine again for now.
I've run some logs and here's some things I've found:
When the latest freeze happened, I got this repeated over 100 times:
Apr 29 11:04:31 jon-turners-macbook quicklookd[536]: CGContextClosePath: no current point.
I've also seen this:
Apr 29 11:18:19 jon-turners-macbook kernel[0]: Previous Shutdown Cause: 3
Apr 29 11:18:19 jon-turners-macbook kernel[0]: GFX0: family specific matching fails
Apr 25 19:19:50 localhost kernel[0]: hi mem tramps at 0xffe00000
Should there be anything else I can check? I would run Apple Hardware Utilities, but I don't have the original disks, just the Leopard installer. I have Disk Warrior, but it seems strange this would happen with multiple systems and drives. I'd like to get Techtool Pro, but haven't had the money/time to order it yet.

Thanks for the replies!
Yeah, I think it's the HDD. I was just worried that the RAM was bad and corrupted the HDD or something, but given the symptoms I think you guys are right. Ordered a 7200RPM 320GB HDD off Amazon Prime...will be here tomorrow
I'll post how it goes after I finish installing it. I'm backing up as I type.
I wonder if I can fix the ir port and the sleep indicator light when I install the hard-drive. The sleep indicator light never turns off. It stays on as long as my computer is on, only turns off when I shut it down.

White Macbook 2006 random shutdown solved removed cpu heatsink and more

I picked up a cheap macbook from a secondhand retailer for $300 and it regularly shutdown, froze, restarted as well as the grey kernel panic screen completely random no real pattern. I set about trying to solve the problem swapping ram and hard drive with my identical 2006 macbook (which I had similar problems with last year, fixed that one with a new battery connector cable). The ram and hard drive made no difference so I downloaded istat menus to see if any combination of cpu voltage, current and temperature were causing the random shutdowns. It seemed when the temperature reached certain values the computer would shutdown or freeze(around 30 to 50 degrees). I'd read on other forums about faulty cpu temperature diodes so I reapplied heatsink compound to the cpu heatsink and checked all the wiring for shorts but nothing seemed to solve the problem. I was ready to retire the computer and use it for spares for my other macbook when needed but I pulled the keyboard off one more time and tried something completely radical. This fix requires some forward planning and software installation but it has completely solved my Random shutdowns completely.
for instructions see my next post *Fix for random shutdowns white macbook*

Ok this is not for the non technical person but it is quite a simple process with the right instructions.
This first step is very important install the software coolbook($10) and fan control (Free)( not smc fan control). Set up coolbook to operate the cpu at the lowest speed and voltage for both power adapter and battery(1002MHz and .95Volts). Remove the keyboard to access the computer logic board (instructions can be found at iFixit). Remove the four screws and two connectors holding the heatsink to the logicboard and gently lift the heatsink out (very important that you leave the fan screwed in and connected). Close the computer back up if you wish to test just gently connect the keyboard and loosly sit the keyboard back in. Restart and reset the pram immediately. Let the computer boot up and then open system preferences and configure Fan Control to your liking. So far no random shutdowns for over a week (was getting many a day previously.

Macbook won't detect external display anymore - Random shutdown injury??

Hi,
my Macbook has the dreaded random shutdown thing happening, often it can't even get through the startup sequence. If I reset the PMU and PRAM and check the disk every week I can keep it running. Applecare are making not particularly helpful suggestions like "run it in safe mode" - hello people, random means it can take days to happen again... I use this computer for work so I need it at full capacity every day!!!
Anyway, enough angry ranting. The casualty of today's RS and subsequent PRAM PMU resetting is my external display (Viewsonic LCD). The macbook is no longer sending signals to it (display says "no signal"). When I ask the macbook to "detect displays" nothing happens. I have restarted the macbook several times and unplugged and replugged the display connection it doesn't help. Yes, I have the AC power cable plugged in on the Macbook (I know it doesn't like talking to the screen if I don't).
The display and macbook have always worked fine together in the past...
Does anyone have any suggestions on how to test for causes or fix this display related problem?
MacBook Mac OS X (10.4.8)
Powerbook G4 Mac OS X (10.4.2)

You don't mention ever having brought the problem to Apple's attention, or what resulted from your request for Apple's help with it. This isn't a universal or widespread problem. It may be a hardware fault in your own equipment that needs to be resolved with a repair, or it may be a software problem (corrupt file, incompatible software conflict, update needed, etc., etc.). You seem to think Apple should have fixed it for you without your lifting a finger, and you're eager to complain about Apple's lack of support. But you've offered nothing to indicate that Apple even knows you need support. You do have to ask for it. Have you done so?
We have no idea what steps you've taken to try to narrow down the possibilities, e.g., making sure the monitor is turned on; trying a different video cable as iVmichael has suggested; testing the monitor with the same cable on a different computer; testing a different monitor with the same cable and then with a diferent cable on your computer; substituting a different cable adapter, if you are using one; applying all applicable system software updates and then Repairing Permissions and Repairing Disk; starting in Safe Mode and seeing whether the monitor is recognized and activated then; seeing whether the monitor is detected in System Profiler; and so on. You may have done some of these things, but you haven't told us about them or about the results.

Overheating or random shutdown?

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