IMac refusing to boot

Hi,
I had a nasty surprise this morning with my iMac (white iMac, C2D, 24"): I powered it up, the fans started blowing like crazy, and then it just powered back down. Nothing else, no display, no startup sound, just that. When I tried to turn it back on, it wouldn't do anything at all. I finally had to pull the power plug, put it back in, and it started again.
I'm wondering if this could come from the dust that accumulated inside the iMac. I'm already having problems due to the fans not cooling the CPU and GPU enough, so I had to increase the fans' speed to compensate. When not doing that, the screen goes crazy and displays weird lines everywhere, until it finally just crashes.
Could it be something else, or just using a vacuum cleaner to remove some dust would solve it ?

HI Fred,
Since you are experiencing startup problems, make sure your important data is backed up to an external source just in case.
If your iMac has trouble starting up again, try Resetting the PRAM
the screen goes crazy and displays weird lines everywhere, until it finally just crashes.
Try the Apple Hardware Test
Might be a good time to boot from your install disc, run Disk Utility to make sure there aren't errors on the startup disk.
Insert your install disk and Restart, holding down the "C" key until grey Apple appears.
Go to Installer menu and launch Disk Utility.
Select your HDD (manufacturer ID) in the left panel.
Select First Aid in the Main panel.
*(Check S.M.A.R.T Status of HDD at the bottom of right panel. It should say: Verified)*
Click Repair Disk on the bottom right.
If DU reports disk does not need repairs quit DU and restart.
If DU reports errors Repair again and again until DU reports disk is repaired.
When you are finished with DU, from the Menu Bar, select Utilities/Startup Manager.
Select your start up disk and click Restart
While you have the Disk Utility window open, look at the bottom of the window. Where you see Capacity and Available. *Make sure there is always 10% to 15% free disk space*
If you cannot boot from your install disc, try booting in Safe Mode
Carolyn

Similar Messages

IMac refuses to boot properly - hardware problem?

Hi all, I'm having some problems with my iMac (purchased last October) and was hoping some kind soul could shed some light.
Here's where I'm at now.
- The iMac doesn't boot. When I press the power button, it chimes, but then nothing happens and I just see the white/grey screen.
- I have disconnected all 3rd party peripherals, and only have original keyboard and mouse attached.
- No matter what keyboard combo I try, nothing happens either. I managed to eject the disc once by pressing the mouse button, but no other key combos work.
- I must have rebooted about 30 times now, and only twice did something happen:
1. Once it sat on the white screen for a bit, and then displayed a grey folder with a questionmark in it, but then nothing else happened.
1. Once I did get it to boot from the CD, and I got to the installation screen. At this stage I tried a couple of different things. First I tried Disk Utility, and the HD is indeed listed in the sidebar (although it's listed as 'disk0s2' rather than 'Macintosh HD'. When I picked the First Aid tab, both Repaid Disk Permissions and Verify Disk Permissions are greyed out (i.e. I can't press them). When I went to press Repair, I got the following error message.
+Verify and Repair disk 'disk0s2'+
+Checking HFS Plus Volume+
+Invalid node structure+
+Invalid record count+
+Catalog file entry not found for extent+
+Volume check failed+
+Error: The underlying task reported failure on exit+
+1 HFS volume checked+
+1 volume could not be repaired because of an error+
So, I could do nothing in Disk Utility. I then thought "well, I'll just surrender then and reinstall OS X", but when I went back to the Install screen and proceeded, and it asked me where to install the OS, there was nothing to choose from. Usually 'Macintosh HD' is listed along with any other disks. Not this time. So, I shut down the computer again, and now I can't back to the screen (i.e. it refuses to boot from the CD again and instead just spits out the disc).
So then I phoned Apple. But because I don't have their service plan (and the free one only lasts 90 days after purchase), he couldn't help much. He did say though that if it spits out the disc, it could be hardware problem, and my warranty would cover it.
So, should I just give up, realise my HD is screwed and my data is gone, and hand it in for service? Or can anyone here shed some more light on my situation?
Even a "yes, you're screwed, hand it in" would suffice, if that's indeed where I am.
Thanks,
Hanna
Edited for spelling by Nunis

Thank you, dwb. I did just manage to boot from the DVD again, but again I'm seeing the same problems.
Screencaps:
http://nunis.net/misc/screencaps/boot.jpg
http://nunis.net/misc/screencaps/boot2.jpg
And I have been backing up, but I just got back from vacation, so my last backup is 2 weeks old and the things I was worried about saving was the work I did on my vacation photos and video. Also, you'd be kicking a girl when she's down, which would be even worse.
I think I'll definitely hand it in now, and ask the tech to rescue whatever data he can. I don't care if it costs me a bit, if it means rescuing my vacation photos.
Thanks again, you've been most helpful.

IMac refuses to boot up - grey screen, first aid failed

Hope someone can help me...
Recently downloaded the latest intel mac securiy update - ver. 11 - since then my iMac began to take a long time to boot up. It started fine this monring but upon shutdown and subsequent restart this evening my machine reaches the grey screen stage and then seems to 'loop' continuously - no log-in screen is ever reached.
I tried power off, unplug all cables - no results
I tried safe boot - no joy either
Booted from back up cds - ran disk utilities
verify disk - it aborted at the catalog check with invalid node structure, 1 HFS volume could not be repaired messages
verify disk permissions - it froze
tried install and archive - message was installation failed
Is there anything else I can try apart from erasing my hard drive and installing from scratch?
This seems to have started since I downloaded the ver 11 intel security update...
any advice greatly appreciated
Hazel

Hi Hazel, and a warm welcome to the forums!
Don't try to Repair Permissions or anything else until the Disk Structure is fixed.
You must repair the HD, if Disk Utility or fsck should fail to repair it, your best bet is DiskWarrior from Alsoft, you'll need the CD to boot from if you don't have another boot drive...
http://www.alsoft.com/DiskWarrior/
But sometimes fsck will work if you do it a few times, not likely, but possible.
Does it boot to Single User Mode, CMD+s keys at bootup, if so try...
/sbin/fsck -fy
Repeat until it shows no errors fixed.
(Space between fsck AND -fy important).
Resolve startup issues and perform disk maintenance with Disk Utility and fsck...
http://docs.info.apple.com/article.html?artnum=106214
Tough without the Tiger Disk problems, but try fsck...
To use fsck, you must run it from the command line. Unlike using your mouse to open an application to do something, you'll need to type a text command at the prompt (#) to tell fsck what to do. The Terminal application (/Applications/Utilities) and single-user mode are two examples of command-line interfaces in which you can type such commands. To use fsck:
1. Start up your computer in single-user mode to reach the command line. Hold CMD+s keys down at bootup. Note: If necessary, perform a forced restart as described in the Emergency Troubleshooting Handbook that came with your computer. On desktop computers, you can do this by pressing the reset/interrupt button (if there is one) or holding down the power button for several seconds. On portable computers, simultaneously press the Command-Control-power keys. If your portable computer doesn't restart with this method, you may need to reset the Power Manager.
2. At the command-line prompt, type /sbin/fsck -fy
(SPACE between fsck AND -fy important)
3. Press Return. fsck will go through five "phases" and then return information about your disk's use and fragmentation. Once it finishes, it'll display this message if no issue is found: 
The volume (nameofvolume) appears to be OK  If fsck found issues and has altered, repaired, or fixed anything, it will display this message: *** FILE SYSTEM WAS MODIFIED ***   Important: If this message appears, repeat the fsck command you typed in step 2 until fsck tells you that your volume appears to be OK (first-pass repairs may uncover additional issues, so this is a normal thing to do).
4. When fsck reports that your volume is OK, type reboot at the prompt and then press Return.
http://docs.info.apple.com/article.html?artnum=106214

Bondi iMac refuses to boot CDs, crazy workaround suggestion, any comments?

Hi
Short question: can I bypass the CD reading process on my Bondi iMac entirely?
By 'cloning' genuine OS8 and/or OS9 CDs and/or Linux ppc distros onto a set of USB drives.
Then using these sticks to dd data onto a bootable partition of the hard drive using finnix (which is about the only distro I can get to work).
Boot from the new (and hopefully bootable) partition, and proceed with the install process from there; the target being a second partition.
Then just rearrange the partitions, tidy up and reclaim the space from the temp install, and there you have it, a working Bondi iMac which has effectively become a very lumpy netbook.
Anyone fancy spelling out in simple steps what to do?
Long explanation: So I bought a lime G3 iBook for spares. That worked out well, I sold the parts for more than it cost me, and I had some software left over. I should keep that; as I don't want to get into copyrighting difficulties, I thought.
So, I bought a tangerine iBook G3. Now by then I was starting to get intrigued. This seeemed like it could be saved, as a personal project. So I swapped the keyboard, battery, power supply, and even the memory for a while. Then I got into the software. Wouldn't load. Apart from finnix. So I put it up for sale - wiped - someone else's problem.
Except then I bought a Bondi iMac, same problem. CDs wouldn't load. Except for finnix, or I'd have given this up as a bad job ages ago...
So, I tried cleaning the opticals. No joy. I tried every OSX and linux distro I could lay my hands on. Nothing but finnix 86.1 worked.
I wondered about booting a net upgradeable distro on the USB, but it's USB1 and no firewire, so no can do.
But then, tonight, I think. What if... I can get (all of!) a genuine Apple CD contents onto the USB on a working CD-ROM, the USB onto a partition of the hard drive (using dd on finnix), boot the installer from the image partition, target the other partition for install, reboot, tidy up, reclaim space, and go about my business.
If that seems over-complicated, I know, I'm obsessive about old tech. And I'm very poor, so selling spare parts rather than buying them is key (or I'd just collect old CD-ROMs instead of the CDs to go in them). But when it comes to data I will not be beat, when I comes to electronics I can't change a lightbulb.
What I've got:
CD-R (lots)
Time (limited - my wife wants the iMac GONE or WORKING!)
A Bondi G3 iMac with a faulty (flakey - but very clean) CD-ROM.
A Tangerine G3 iBook with the same problem, but worse.
A working DVD/CD-R/W Windows XP machine.
A working Ubunbtu server with a CD-R (and with fairly tricky access - so no gymnastics please)
If you've got this far, you'll have had a similar problem.
I'm kind of at the meh, sell em, nah, fix em, erm, kind of stage. So sorry if I've wasted anyone's time.
Look forward to hearing from you.

I wondered about booting a net upgradeable distro on the USB, but it's USB1 and no firewire, so no can do.
The firmware doesn't support boot from a USB drive.
Robert

Early G5 iMac refusing to boot-up

Installed sons new 'Battlefield 1942' this morning, all worked fine until he paused game (for 2 minutes or so).
Screen went 'all funny' many lines etc on screen etc - can't be more specific than that.
We restarted iMac, all appeared fine for a few mins, then problem reappeared.
Restarted again, installed a Sims2 extra (university) and with in 5 mins same problem
Rebooted and again, now having reset PRAM (twice), unplugged powerlead etc cannot get more than 15secs into booting up, before more squigly lines and a message about having to restart etc
Unable to even eject the Sims2 expansion DVD to reboot off iMac DVD
Am open to suggestions, even as to where in Norwich (UK) area to take it first thing wednesday am for open-heart surgery.
OK, so I have this power-book to write this plea for help, but important business files are on there! (of course)
HEEEEEEEEEEEEEELP
Patrick
G5 iMac, 80Gb Drive Mac OS X (10.3.9) 512mb RAM,
G5 iMac, 80Gb Drive Mac OS X (10.3.9)

Miriam, and all other readers, I am typing this response on my newly repaired iMac G5, although it seemed to take a long while I waited for my 'local' (40miles away!) AASP to reopen after the new year break, I was asked to take it to them, and leave it "for when our engineer finds time to look at it".
Now by quoting them it may seem a little unfair, as within 4 working days of leaving it with them, they rang me to ask to address it could be couriered.
It arrived back today, although with no explanation as to exactly which components were replaced, but. hey! its back, up and running and I resume no repair bill for me to pay.
In conclusion then, I would like to thank GeTech in Ipswich for arranging the repair, Apple for 'OK-ing' the repair, and Miriam, for pointing me to the article on these pages which let me know I was not alone.
I am really glad I had my older Powerbook to keep me connected (albeit creaking along at times!), and if only I could get that machine to print (anything) again it would be even better.
Yours sincerely folks, Patrick Beane.
BTW, does anyone else reading this know if the replacement parts are 'beef-up' to prevent this re-occuring? (I am going off topic here, back in the early eighties I had an HONDA CX500, these were prone to Camchain tensioner breakages, by the time mine failed and HONDA repaired it, I am led to understand by the dealers mechanics that that the new parts could tension an oil tanker anchor chain)

My older i7 core iMac refuses to boot off install DVD

Can't seem to reboot off install discs. Stripped & reformatted couple year old i7 Core iMac 27" for Wifey at Christmas, and no iphoto, and finally noticed no way to download. spits out install discs like chewing tobacco.
OS 10.6.8, 2.8GHz i7 core, 12gb ram.
What on earth is going on???
Anyone got any clues?

The first thing to try is a drive cleaning disk. A dirty optical drive can cause that symptom. The dry type with fine brushes works best for me.
As these cost only US$5-15, they are an ecomonical first step that may revice the drive.
A friend had a Mac doing what your is and was told by a certified Apple tech that his drive was dead and required replacing--about US$150 for his model. I loaned him my cleaning disk and that was sufficient to restore the drive to 100 percent function.

Please Help :( iMac 20" refuses to boot up with anymore than 1gb ram?

Please Help iMac 20" refuses to boot up with anymore than 1gb ram? It was fine 4 days ago and had been working with a 1gb stick in one slot and a 2gb stick, which had replaced the orignal 1gb stick that I got it with, in the other and it had shown 3gb of ram and was working just fine with that since November? It went to sleep briefly 4 days ago while I was waiting on a customer and I came back to try to wake it up and it never would forcing me to hard boot it. When I did that it would only go to a black screen with a solid white light on the power indicator. Over and over again and same thing. I read and tried every suggestion I could possibly find in this and a few other mac forums to no avail.
I finally after reading about RAM issues etc. I decided to power off and take out the ram sticks and try them one at a time in each slot. So I took out the 2gb stick and did the SMC reset and it would boot up and work just fine with the 1 gb of ram. So then I went through the same process with the 2gb stick and it would not boot up only go to a black screen with white solid light again (NOT flashing). So then I tried the other original 1gb I had replaced with the 2gb and it worked just find like the other 1gb. So then I tried just 1gb stick in the other ram slot (back facing one) and with just the 1gb strip it booted up and worked fine. Tried it with the other 1gb stick and once again that one too worked just fine. So I determined it wasn't the slot itself I thought? I then tried the 2gb in the back slot and it would not boot only go to the black screen white solid light deal like before. So I thought well ok it's obviously the 2gb ram must have somehow went bad (even though I have only had it since November) and I thought well I will just use the (2) 1gb sticks in each slot and then that will at least give me 2gb because only 1gb really ***** LOL. So I proceeded to go through the same shut down process installed both sticks (I always push them to I feel them click and my fingers have a nice indention on them) reset the SMC and turned the power one and.... It would only go to the black screen with white solid light on power indicator???? I went through the same above process at least 3 times and again today a few times and I can't figure it out and I tried to search and search and I couldn't find anything like what I am experiencing.....What happened? Please help this slow Imac is killing me. It will work with 1gb ram only nothing more? Here are the specifics of my Imac.
It is a 20" Late 2006 Intel Core 2 Duo 2.16 ATI Radeon X1600 256 MB graphics card and Ram with now only 1gb (did have 3gb) and I am running OSX Lion 10.7.5
When I go to system report and go under memory it shows this:
BANK 0/DIMM0:
Size:          1 GB
Type:          DDR2 SDRAM
Speed:          667 MHz
Status:          OK
Manufacturer:          0xCE00000000000000
Part Number:          0x4D342037305432393533435A332D43453620
BANK 1/DIMM1:
Size:          Empty
Type:          Empty
Speed:          Empty
Status:          Empty
Manufacturer:          Empty
Part Number:          Empty
Serial Number:          Empty
Any help I can get would really be appreciated. Thanks in advance
ALSO...Here is also a pic of the system log right before it happened. It even changed the date to 07/2014????
I have some more if needed???????????????
<Personal Information Edited by Host>

The Memtest just completed and came back like this? It only test the single 1gb chip because anything more in this computer it won't go past the black screen with solid white power light.
Memtest version 4.22 (64-bit)
Copyright (C) 2004 Charles Cazabon
Copyright (C) 2004-2008 Tony Scaminaci (Macintosh port)
Licensed under the GNU General Public License version 2 only
NOTE: No command-line arguments have been specified
Using defaults: Test all available memory, one test pass, no logfile
Mac OS X 10.7.5 (11G63) running in multiuser mode
Memory Page Size: 4096
System has 2 Intel core(s) with SSE
Requested memory: 250MB (263086080 bytes)
Available memory: 250MB (263086080 bytes)
Allocated memory: 250MB (263086080 bytes) at local address 0x0000000101000000
Attempting memory lock... locked successfully
Partitioning memory into 2 comparison buffers...
Buffer A: 125MB (131543040 bytes) starts at local address 0x0000000101000000
Buffer B: 125MB (131543040 bytes) starts at local address 0x0000000108d73000
Running 1 test sequence... (CTRL-C to quit)
Test sequence 1 of 1:
Running tests on full 250MB region...
Stuck Address       : ok
Linear PRN          : ok
Running comparison tests using 125MB buffers...
Random Value        : ok
Compare XOR         : ok
Compare SUB         : ok
Compare MUL         : ok
Compare DIV         : ok
Compare OR          : ok
Compare AND         : ok
Sequential Increment: ok
Solid Bits          : ok
Block Sequential    : ok
Checkerboard        : ok
Bit Spread          : ok
Bit Flip            : ok
Walking Ones        : ok
Walking Zeroes      : ok
All tests passed! Execution time: 362 seconds.
logout
[Process completed]
Seems Okay I guess?

IMac 2.4GHz (MA877LL) refuses to boot with 4GB ram, boots only with 3 GB

iMac 2.4GHz Core 2 Duo 20" Anodized Aluminum (MA877LL)
iMac 2.4GHz (MA877LL) refuses to boot with 4GB ram, boots only with 3 GB
2 x2GB Geil GX2S6400-4GDCA
Computer refuses to boot with both chips installed 4 GB.
Computer will boot and recognize 3 GB..( Apple 1 GB + 2 GB GEIL)
Both Geil Chips will boot, when paired with the Apple 1 GB chip.
machine recognizes 3 GB ram.
Please advise...

Ensure the computer's RAM is fully seated down, and then try resetting the PRAM by holding down options-command-P-R at boot. The computer will make the boot chimes and then reset and chime again. When it chimes the second time release the keys and let the thing boot normally. Hopefully that will let it recognize the RAM.

24" iMac won't boot!

My 24" iMac is around four years old, and running Leopard v.10.5. It froze up yesterday while playing tunes in iTunes. I had to do a hard restart (with the on/off button on the backside). And now, it will not boot. I get the "tone", then the Apple icon, then a blank light gray screen. I tried booting from the OS disc, but this gives me a blank light blue screen, rather than the normal light gray. I even tried booting from my Alsoft Disk Warrior which I bought for my new MacBook Pro. Didn't work. I tried unplugging the machine overnight, but still no help. Tried zapping the PRAM, but nothing.
I replaced the HD myself last year when it crapped out. This new problem does not act the same as when the HD went bad.
Am I screwed? Suggestions?
Thank you-

Can you provide a little more detail around the grey screen? Does it get to the grey screen and then start the boot process and get stuck with the little spinning grey circle? If so I suspect that the boot sequence is getting stuck on a device driver (.kext file). Hopefully you can get into single user mode by pressing the cmd and S key during boot up. The other option would be to try to get into safe-mode by pressing the shift key while booting this might help you. I have a 24" early 2008 one and when I bought it off of ebay I need it had booting problems. It would get stuck at the grey screen with the apple and the spinning wheel. After pouring through the internet and taking a drive from my other imac that has boot camp installed I was able to get the machine to boot into Windows but not into the Mac OS. Fingured out the the video card was the culprit and Windows just set it to VGA while the MAC OS was more specific and refused to boot. I got the idea to replace the video driver on the mac side with something generic but couldn't figure out how to do it. I found on the net that I could just delete the offending .kext file from the Extensions folder and the machine started. However this does not allow me to change resolution and requires me not to do any updates that might reset the extension files. Let me know if any of the above works if not I might be able to at least help with getting the machine to boot.

IMac won't boot from HDD or CD. Help!?

Hi,
I recently came back from holiday for a couple of weeks and sat down to start my iMac (24" C2D). The machine just sat at a white screen and wouldn't go anywhere. Thought, ah, I'll just reset the PRAM (unplugged power cable for a min or so), and still same problem. Eventually I got the mac to boot by holding down the power button, the long beep sounded and the mac booted. All was well, until the next time I powered it down. Same thing, however same resolution didnt work...
After numerous attempts holding c, I've managed to boot into the mac installer, which said it couldnt repair the drive through disk utility. As I have time machine backup, thought I'll just start from scratch. Created a new partition (just to make sure everything was fresh), verified disk (no problems), started installer and it crashed towards the very end of the install (just over 1 hour in) with errors of being unable to copy files. After another few hours, managed to boot from CD again, this time install started, left it running overnight, only to find the mac in the morning on, but with a black screen. I've had to power it off and now I'm left with the same issue of a white screen and being unable to boot from CD.
Does any of this make sense to anyone? Could be a failed HDD, but why would I have the issue with the iMac generally refusing to boot from CD? Ran hardware diagnostic (extended) and no problems found.
I now have no hair left...

I assume that model has a back up battery in it? If so, have you changed it recently? If not you may want to replace it. In the meantime, try removing it completely and see if it starts up any better. If the battery is right on the hairy edge of good/too low, it might be corrupting the PRAM (or whatever they call it now on new models) causing start up issues. If you remove it, you won't retain a lot of settings such as Date and Time, but you should also be able to boot up eat time with all default values.
I had the same sort of issue with my eMac and pulling the battery cleared it up. That was many months ago and one of these days I might get around to buying a replacement battery... or not.
Cheers,
Patrick

HT3964 I am not able to reboot my Mac desktop. When I switch on the Mac, I get a white screen with the Apple logo and the little wheel below that goes round and round but the computer refuses to boot.

Hi, I am not able to reboot my Mac desktop.
When I switch on the Mac, I get a white screen with the Apple logo and the little rotating circle.
The system refuses to boot.
What can I do?
Marcus

We need to get you moved. This forum is for mini-tower Macs built between 1998 and 2005 and doesn;t get as much traffic ("eyeballs on the problem") as the forums for newer Macs.
Please do "About this Mac" from you Apple menu and tell us what that says for "processor" and Mac OS version. Looks like this:
or this for later Mac OS versions:
With that we can figure out which of the two iMac forums you need and get the Hosts to move your post.

IMac won't boot into OS X after failed software update

I've got a 400MHz G3 iMac here, running 10.4.8. I finally got it connected to our network and ran Software Update, and it downloaded the 10.4.11 update. A few of the other updates installed successfully (iTunes phone driver, Java updates, etc.) but I got an error on the 10.4.11 combined update installation. Rebooted to finish installing the other updates thinking I'd try the 10.4.11 update on its own, and now the iMac refuses to get past the "Welcome to OS X" screen (I get the window with the Apple logo and the progress bar, but the progress bar never moves, even after several minutes). Tried safe boot with no luck.
There are no peripherals connected except the Apple keyboard/mouse (which are connected via a USB extension cable), so I can rule those out. Basically I'm wondering what steps I can take before I have to dig out my Tiger disc and mess around with Disk Utility...
Thanks in advance!

Preexisting corruption is my guess.
"Try Disk Utility
1. Insert the Mac OS X Install disc, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*
3. Click the First Aid tab.
4. Select your Mac OS X volume.
5. Click Repair. Disk Utility checks and repairs the disk."
http://docs.info.apple.com/article.html?artnum=106214
Then try a Safe Boot, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, reboot when it completes.
(Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive.)
If perchance you can't find your install Disc, at least try it from the Safe Boot part onward.
The usual reason why updates fail or mess things up, is if Permissions are not fixed before & after every update, with a reboot... you may get a partial update when the installer finds it doesn't have Permissions to change one obscure little part of the OS, leaving you with a mix of OS versions. (Well, the Installer actually uses superuser Permissions to do it's work, but after reboot it doesn't guarantee communication with other existing needed files Permissions.)
Some people get away without Repairing Permissions for years, some for only days.
If Permissions are wrong before applying an update, you could get mixed OS versions, if Directory is the slightest messed up, who knows!
If many Permission are repaired, or any Directory errors are found, you may need to re-apply some the latest/biggest updates.
May even need to do an Archive and Install if you have room on the HD, but saves all your files and gives a new OS...
http://docs.info.apple.com/article.html?artnum=107120
I only use Software Update to see what is needed, then get them for real via...
http://www.apple.com/support/downloads/
That way I can wait a week or so, check the forums for potential problems, and get Permissions & such in order before installing.
If all the above fails, then it appears to be time for a relatively painless Archive & Install, which gives you a new/old OS, but can preserve all your files, pics, music, settings, etc., as long as you have plenty of free disk space and no Disk corruption, and is relatively quick & painless...
http://docs.info.apple.com/article.html?artnum=107120
Just be sure to select Preserve Users & Settings.

IMac won't boot Macintosh HD or 10.6 DVD

Hello,
Yesterday, after rebooting back into OS X from Windows 7, my iMac displayed a progress bar underneath the spinner and Apple logo. This took about 10 minutes, but did eventually boot back into the OS. All of today, my iMac has been working fine, but a little while ago, I thought about that yesterday and decided it'd be best to run Disk Utility to check to see whats going on.
It repaired a whole load of permissions, and reported some errors with the disk, instructing me to boot from the install DVD. Unfortunately upon doing so, the computer refused to boot the disk. It just stuck on the grey Apple logo screen for about 10 minutes (with no spinner), before I'd had enough and turned it off.
As I've had a similar thing happen before, I knew to try using Target Disk mode with my 2007 model iMac – this works, and recognizes both the Mac and Windows partitions of the HD. I'm currently copying off the movie project I was working on in Final Cut today that hasn't yet had a chance to be backed up by TM. I also plan to back up my Windows partition as a whole to restore later if need be.
Right now, I'm using my iPad to type this, and wondering what would be the best thing to do. Is this just a simple matter of restoring my TM backups and reinstalling the OS using Target Disk mode, or is there anything more to it? Is it worth attempting to repair the disk using the second iMac / any ideas as to what I can do to fix this. I'm presuming that Windows 7 has caused this because just before I rebooted into OS X and first discovered the issue, Windows Explorer crashed when trying to access the HSF+ formatted Macintosh HD. When trying to boot the DVD, on the boot menu, Macintosh HD now shows up as EFI Boot. I'm presuming this isn't a hardware issue with the drive itself, as it is perfectly happy to boot Windows / copy files off / work fine all day, and only seems to have an issue with booting.
Really I'm just asking if anyone can see what I can do to avoid a lengthy (if not particularly hard) restore process / anything I'm doing thats going to make things worse / any other tips etc.
Thanks,
Sam.

Zanorath0 wrote:
It repaired a whole load of permissions, and reported some errors with the disk, instructing me to boot from the install DVD. Unfortunately upon doing so, the computer refused to boot the disk. It just stuck on the grey Apple logo screen for about 10 minutes (with no spinner), before I'd had enough and turned it off.
Is it possible you have mixed up your old & new grey iMac installer discs? An older one for a 2007 iMac will not start up a new 27" iMac -- it lacks all the drivers & associated files for the new one's hardware. The same is true for at least the original Snow Leopard retail disc: it contains just 10.6, not the later build version your 27" iMac needs.

Intel iMac will not boot past gray screen

Intel iMac will not boot past gray screen
my system:
new (month old) 24" intel imac, 2.8 ghz, 4 gb ram.
running: leopard (upgraded from tiger, which was pre-installed at purchase), installed 10.5.1 update right before this huge problem occurred.
install discs on-hand: two-disc tiget set, single leopard upgrade disc.
what led to this:
i wanted to install windows using bootcamp on a 50 gb partition.
at this point i was running leopard 10.5
i followed all bootcamp instructions, printing out the guide, as well. once i got into the windows setup, i was prompted to choose a partition to install windows. unlike the bootcamp guide, which showed three partitions, one clearly labeled "bootcamp", i saw only one partition. not wanting to risk writing over my mac partition, i quit the setup and rebooted the mac os. after some googling around, i looked for firmware updates (didn't need any), and then software updates. i decided to try updating to 10.5.1.
i then ran through boot camp again, deleting my previous windows partition, creating a new one, and moving forward as before. once again, i was only shown one partition to choose from in the windows setup. i exited the setup again to reboot through the mac os, but this time, i was only given a blank gray screen.
here's what i have tried so far:
booting from a CD, holding down the C or D keys: no response (in fact, i have to restart the computer holding down the mouse button to be able to eject the CD)
booting with option key held down: gray screen
booting with option key held down with external bootable firewire drive attached: the firewire drive appears as a boot icon, and i can click on it within a five second window, but then the screen freezes after that time period, and nothing changes
booting into target mode while attached to another mac: gray screen (no firewire icon, and drive never shows up on other mac)
resetting NVRAM: i'm able to hear the boot chimes, but no difference in performance. gray screen every time
Safe boot: nothing but a gray screen
Verbose mode: gray screen
Single user mode: gray screen
Single user mode with firewire drive attached: occasionally (not every time), i am able to get the white on black terminal to show up. from here, i'm able to run fsck, but it appears to only be checking the firewire drive. i have tried several times to boot from here, and once it took me to a blue screen with movable arrow cursor, but it never went beyond this.
is there anything else left to try before taking it to apple?
any help would be greatly appreciated.
thanks,
Casey Burns
Casey Burns Illustration and Design
http://CaseyBurns.com

I'd call Apple support at this point. You'll need
to put this issue on the record.
Call U.S. iPod and Mac technical support: 1-800-APL-CARE (1-800-275-2273)
The wait may be long for an agent to come on the line
so expect that and have some other stuff to do in the meantime.
If you have the applecare protection plan, I'd ask about "onsite"
service.
I like your work ! Good luck !
Slim
Message was edited by: slimpikkunz

My iMac can't boot Windows 7 From USB while my Macbook Pro can do it

I install Windows 7 64 bit and rEFIt into a USB hard disk and hope to boot from my iMac 27" (2010 Mid). However, it shows that no boot deivce is found.
If I plug the SAME disk to my Macbook Pro 17" (2009 Mid), it can boot Windows 7 without any problem.
I tried with Linux and get same result, iMac says no boot device while my Macbook Pro can boot it without problem.
I tried experiment for weeks and still can't get iMac work.
I think it is very abnormal and I wonder if someone can tell me how to fix it or any directory to solve this problem.

My iMac runs snow leopard and my MacBook pro runs Lion. Both of them are updated with latest updated. I just get one external USB hard disk with Windows 7 32 bit installed and magically, my iMac can boot it from rEFIt. However, I don't know what makes it works. I tried to make same configuration, software and steps on other USB hard disks for hundreds times but I can repeat it again. All other attempt can make USB hard disk boot on MacBook Pro but not iMac only.

IMac refusing to boot

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