My Apple iMac MB418LL/A 24-Inch Desktop suddenly turned off

My iMac MB418LL/A 24-Inch Desktop suddenly turned off and now doesn't respond to the power button even after the SMH (right acronym?) reset procedure.

Please do not startup duplicate topics.
I replied to you here > https://discussions.apple.com/message/18090261#18090261

Similar Messages

IMac 2008 emc 2211 suddenly turns off and back on, RAM problem?

I have an iMac from 2008 emc 2211.
Two years ago i upgraded my RAM from 2GB to 4GB Crucial memories.
Two weeks ago my imac started to suddenly turn off and back on inmediatly. Recently it stared to happen more often to the point that it can't boot completely and show the desktop
I checked the power source and it was fine.
I opened the computer and pulled out the power supply and it seamed to be fine.
I tried to run the hardware test with the disk that came with the computer and it can't even finish the test because it turns off.
Before it couldn't boot anymore i checked if it was overheathing with smcFanControl and the temperature was always around 44C, so it was fine.
Could this be the crucial RAM that is failing?
thanks in advance.

Ok, i've replaced the RAM and the power supply and the problem persist, so it seams to be the logic board that is failing.
Any ideas?

My mac book air turn on with grey apple icon and spining wheel. then it wont turn off.

my mac book air turn on with grey apple icon and spining wheel. then it wont turn off.pls help

Have exactly the same problem with my wife's MacBook Air. After restaring in Restore mode and trying to repair the disk (Disk Utility showed errors in the verification), the system tells me to backup as much data as possible (how?), re-format the disk and restore backed-up files. Error comes up when "updating boot support partitions for the volume as required".
Original restart action was done due to software update requesting it, if I remember correctly, iTunes was updated.
I don't want to start a painful back-up procedure (although I do regular back-ups): how should I know, where iPhoto stores it's data or where my mails are (yes, still using local mail)? How can I access the data if I can't boot?
My iMac's disk crashed also a couple of months ago and I'm still recovering. I have four Apple devices, two of them have failed. Can Apple afford such a ratio?

IMac i7 - Suddenly Turns Off

The iMac suddenly turns off while I'm working. I've owned the unit since August 2010 but this problem has just started occurring. I think it has happened three times in the past two week.
I've heard about this problem, but have not experienced it until the past couple of weeks. I do have Crucial RAM installed. Before I go to too much trouble, or take it into Apple, I thought I'd check the forums to see if anyone has nailed the problem or come up with a solution.
I there is an easy solution I would be most grateful.
Thanks if you can help.
Linda
Message was edited by: Linda - PBCS

I think your random shutdowns are caused by RAM incompatibility. This problem has been widely reported in this Discussion, and if you do a search by keywords “random shutdown” or “sudden shutdown” or “turn off,” you’ll find dozen threads on this subject.
1) First, did you add RAMs to your iMac? If you have 16GB installed, go down to 12GB i.e. pull out the 8GB you added and reinstall the 4GB that originally came with the iMac. If you need 16GB, purchase 16GB of Samsung brand RAM.
2) Although the shutdowns are generally associated with people who upgrade to 16GB, it does happen with 8, 4, or 12GB and with factory-installed RAMs. If this is your case, pull out the RAM from the slots, and see which RAMs you’ve got. The factory-installed RAMs in the iMac can be made by Samsung, Hynix, or Micron Technology. Whatever RAMs you get, change with Samsung RAM you purchased from a reputable seller.
3) The RAM fix is very easy, fast, and works instantly. My advice as a fellow Mac user is to do the RAM fix BEFORE you call Apple, because apparently Apple does not acknowledge this problem and will do everything for you (change power supply unit, mother board, and eventually the entire computer) but not the RAM switch, without solving the problem.

My Imac will suddenly turn off without warning and then take several hours before it will switch back on again

My Imac will suddenly turn off without warning and then take several hours before it will switch back on again. Can anyone advise?

I like that third tag...
There's really no telling what the problem might be - you may want to try running the Apple Hardware Test (if you can) to see if you've a hardware issue. If you can't even get to the AHT, you've no option but to take the machine into your local Apple Store or an AASP and have them run diagnostics on the machine.
Sorry,
Clinton

IMac G5 suddenly turned off!

Hi,
My iMac G5 suddenly turned off and looked like the power cable disconnected. But I am sure outside of the iMac, the power is no problem.
After this, I tried to power on my iMac G5 with the power button, iMac got a loudly beep sound with the light flashing. Although it can startup to the login window, but when I login to system, again, the iMac was dead with the same situation.
Then power on again, same sistuation was still there (loudly beep sound with the light keeping flashing. Now, after login, the system seemed to be good till now (2hours).
Anyone can help me to figure out the porblem? Is it possible that iMac got the high temperature (because here my room is a little bit hot)
Thanks!

Welcome to Discussions - which model do you have (how to identify your iMac)? It may be that your power supply unit is failing, see if you qualify for either of these Rev A and Rev B repair extension. You might also try cleaning the air vents and vacuuming the inside of your machine (don't open it if it's an iSight). Some people train a fan on the rear of their iMacs if their rooms are very hot, it helps keep the computer cool.
Miriam

IMac suddenly turned off

Hi,
I was working on a word document and my iMac just suddenly turned off and cannot be turned back on.
I have tried SMC reset but no luck. Can someone please help?
Thanks.

Try plugging into another outlet it may be the outlet you are using. Does it make any sound at all or have any video.
Finally complete your profile, you will not get help without giving us any clues. The profile is there for a reason, your post is like says "my car is broken what is wrong?"

Since I upgraded to OS 10.6.8 from 10.5.x my 2x3GHz quad-core Intel Xeon desktop spontaneously turns off as if I pulled the plug. Mostly it happens when there is no open software and it's in the sleep mode, but it has happened while I'm working.

Since I upgraded to OS 10.6.8 from 10.5.x my 2x3GHz quad-core Intel Xeon desktop spontaneously turns off as if I pulled the plug. Mostly it happens when there is no open software and it's in the sleep mode (because it spends more time like that), but it has happened while I'm working. It just suddenly quits.

This is a suspicious sign of power supply failure. I would have that checked into. Others who have had similar problems have had the power supplies replaced which fixed the issue.

I'm selling my iMac. i don't know how to turn off my access to iCloud. so purchaser can't access my files

I'm selling my iMac. i don't know how to turn off my access to iCloud. so purchaser can't access my files

What to do before selling or giving away your Mac

My iphone 4 died even though it had plenty of battery, and shows no sign of life until i put it on to charge where it shows the apple sign every now and then but just turns off again after a few seconds.....HELP!!!!

my iphone 4 died even though it had plenty of battery, and shows no sign of life until i put it on to charge where it shows the apple sign every now and then but just turns off again after a few seconds.....HELP!!!!

Could be a defective battery, you should get it checked by visiting an Authorized Apple Service Provider or Apple Store next to your place.
Find an Apple Authorized Service Provider

I can't remember my old apple-id and password so I can't turn off find my iphone. How can I turn it off?

I can't remember my old apple-id and password so I can't turn off find my iphone. How can I turn it off?

Find your AppleId: http://support.apple.com/kb/HT5625?viewlocale=en_US&locale=en_US
https://iforgot.apple.com/appleid
Forgotten passcode or disabled because entered incorrect passcode too many times:
http://support.apple.com/kb/HT1212?viewlocale=en_US&locale=en_US

Was watching a movie with AirPlay mirroring on apple tv from iMac. Got a Skype call. Turned off AirPlay on atv and on iMac. Could not hear my Skype caller until I unplugged the atv. What else could I have done?

Was watching a movie with AirPlay mirroring on atv from iMac.   Got a Skype call. Could not hear caller until I unplugged atv. Turned off AirPlay on both atv and iMac. Could not hear Skype caller until I turned off atv. What else could I have done?

I checked and found that the router did not have the latest firmware.   It does now.   The issue is still there.   I did a little research and found that the model number of my Apple TV (MC572LL/A) shows that it is a 2G version which uses the A4 chip.   The latest version uses the A5 chip and is 1080 capable. Both are supposed to be capable of using type "N" routers.   I don't think that should be an issue but I wonder if later updates may have introduced some issues in the 2G version.
I am going to try changing the "N" channel also- just to see if that makes any difference. The istumbler app does not show any "N" networks in my area so it is defaulting to 149.   I will note that even 1 foot away from the router I only get 75-85% for signal.   I would expect it to be 100% since it is so close.   I am also seeing noise go up from typically 13% to 21% when it is on channel 3 and that close.       I will play change locations and channels and see if there is any improvement.

Well-used iMac suddenly turning off

My not-so-new 20" iMac is turning off on me. I have used this computer, many hours a day, for several years now. For the past 20 months, I've lived in an apartment with old outlets that haven't been replaced, and don't have great contact with the electrical plugs. I've been using a power strip, and the computer only turned off when someone knocked the plug out of the outlet or bumped "reset" on the power strip.
Starting yesterday, my computer started turning itself off (apparent power failure) without anything getting bumped. I'm not seeing any changes in the lights around, me, either, so I don't think that power fluctuations are the proximate cause. I've fiddled with all of the pulgs, unplugged and replugged them, and the problem is getting worse: my computer is shutting off more often. I'm using my spouse's laptop to ask this question, because it's gotten to the point where my comptuer really isn't useable. I've gotten great advice from these forums before, and I'm looking forward to getting good advice this time.
Could a power regulating power strip solve my problems? I'm guessing no, but should I do this in the future, to prevent damage to my computer? More importantly, what is likely wrong with my computer, and about how much would it cost for me to replace the part, or get it fixed at the Apple store? I did not purchase any extended warranties, so this computer is completely out of warranty.

It's been a month since I first posted, and I've got more clues and details now. After I posted my question I realized that my computer is and has been on a surge protector (and the protector light is light), so on later reflection I don't think the problem is the steadines of the power.
den.thed's suggestion seemed to work at first, although I think the longest my computer has gone without shutting down in the last month was about a week, and at this point resetting the SMC doesn't seem to be helping (not that I've turned the computer back on without unplugging it, so I haven't tested this precisely).
I leave my computer on at night (sometimes I put it to sleep, sometimes it puts itself to sleep, but sometimes something happens and the computer doesn't put itself to sleep, or my cats step on the keyboard and wake it up), and it has not shut down at night. It only shuts down when I'm sitting in front of the computer, using it. This made me think I might be having a software problem, so I tried avoiding using specific programs, but I can't isolate a specific program that is always open or always being used when my computer shuts itself down. I think my computer has only shut down while I'm typing, but I'm not certain on that one. I'm using a logitech wireless keyboard (because I spilled water on and destroyed the original keyboard), and (because I only have the one keyboard at the moment) I haven't tried using another keyboard.
Last night I had the realization that the times my computer was going longer without shutting down was when I'd unplugged my backup HD running Time Machine (because of the limited number of USB connections on the computer). I am not certain if my computer has ever shut itself down with the external HD attached. I have had successful saves to Time Machine on my external HD while dealing with this problem.
But these two clues: maybe shutting down only when external HD is plugged in, and definitely only shutting down when when I'm sitting at the computer, actively using it, don't seem to me to point to the same problem.

IMac 27" Intel core i7 doesn´t turn off.

I have a iMac 27" and when i want to turn it off, it doesn´t work. you can see a white background with a little circle. What can i do that my iMac turns off?

Hi, first off - your profile shows an older version OS - is this correct?
Hopefully you have the latest Updates etc,, Initially I would try to Boot from the original apple disks.
The HD might be the culprit. so hopefully you have TM or another bootable back-up!
As your Mac is relatively new I would call AppleHelp or visit your local GeniusBar or AASA..
ps. I spent many happy hours in Liverpool (the Beatles era) - Great City, Great People....L

Time Capsule and G5 iMac - excellent (once Norton Anti-Virus is turned off)

Set up my new 1 TB Time Capsule last night and connected it via ethernet to my G5 iMac (currently TC only in bridge mode to my existing router - but I wll configure the TC as a router and remove my Cisco WAG 54 G tonight).
Worked stright away but VERY slow (i.e: 1 GB per hour transfer)...
Checked the forum and discovered that someone had suggested turning off your anti virus before running Time Machine.
Turned off Norton 10 (I have been meaning to remove this for sometime anyway - it is huge, cumbersome and ***** resources out of my G5.).
Time Machine then ran beautifully. Backed up 200 Gb to the TC overnight. The TC wasn't particularly warm to the touch either while it was backing up (I had also configured it for 802.11.n 5GZ wireless). Thought it would actually be quite warm.
Also - nice Gbit switching between my iMac G5 and PS3 (I'm currently serving up content from my iMac to PS3 using a DLNA server software from ELgato - EyeConnect. This also ran much faster (previous Cisco router/switch was only 100 Mbit).
VERY impressed Apple.
Now - let's see how well the TC performs tonight as a router with Port Forwarding....
cheers
Steve

Set up my new 1 TB Time Capsule last night and connected it via ethernet to my G5 iMac (currently TC only in bridge mode to my existing router - but I wll configure the TC as a router and remove my Cisco WAG 54 G tonight).
Worked stright away but VERY slow (i.e: 1 GB per hour transfer)...
Checked the forum and discovered that someone had suggested turning off your anti virus before running Time Machine.
Turned off Norton 10 (I have been meaning to remove this for sometime anyway - it is huge, cumbersome and ***** resources out of my G5.).
Time Machine then ran beautifully. Backed up 200 Gb to the TC overnight. The TC wasn't particularly warm to the touch either while it was backing up (I had also configured it for 802.11.n 5GZ wireless). Thought it would actually be quite warm.
Also - nice Gbit switching between my iMac G5 and PS3 (I'm currently serving up content from my iMac to PS3 using a DLNA server software from ELgato - EyeConnect. This also ran much faster (previous Cisco router/switch was only 100 Mbit).
VERY impressed Apple.
Now - let's see how well the TC performs tonight as a router with Port Forwarding....
cheers
Steve

My Apple iMac MB418LL/A 24-Inch Desktop suddenly turned off

Similar Messages

Maybe you are looking for