Level 1

67 points

iMac Can Only be Booted in Safe Mode (Shift Key held down)

Since purchasing my 27" 2.8GHz i7 iMac in Nov. 2009, I've updated the OS several times and never had this sort of problem before. I'm now running OS 10.8.3. Last night, while my daughter was displaying photos and video on the iMac in iPhoto, the computer suddenly froze. I had to hold down the power button on the back left and then I pressed it again to boot. But it refused to boot. I would display the gray screen, then the Apple logo, then the spinning spiked wheel, and then the spiked wheel would vanish. After that varies each time I try to cold boot. Mostly, the spiked wheel vanishes, then so does the Apple logo, and then seconds later the Apple logo reappears and stays there. There is a lot of hard drive access for about 15 minutes, and then it stops.

I booted with CMD-R held down and fired up Disk Utility. I tried to repair the disk, but it said it was OK. I then repaired Permissions. But when I tried to boot, I got the same lockup when the spinning spiked wheel vanished.

Interestingly, I can hold down the shift key and boot into Safe Mode just fine, every single time I try.

I had previously put Mountain Lion on an 8GB USB Flash drive, so I booted into Safe Mode and then started the OS X Mountain Lion install (installing on my iMac's internal hard disk, the same disk I am having boot problems on). But even after reinstalling the OS, I cannot boot normally. I still can boot into Safe Mode. I booted into Safe Mode and then applied all the OS X updates. But even then I still cannot boot normally. I can only boot when I hold down the Shift Key (booting into Safe Mode).

I have read that Safe Mode basically just disables Kernel Extensions. And I see there are many inside /System/Library/Extensions (but none in /Library/Extensions/). Could I selectively disable some of these extensions, like I used to do in OS9 via Conflict Catcher, such that I could find the culprit and then boot normally again? (I've read that the Kernel manages extensions itself, but obviously, it's not doing that now, as evidenced by the fact I can only boot when I hold the Shift key down!)

Obviously, if I can reliably boot in Safe Mode, then whatever Safe Mode is disabling is the culprit. So if I could find out what that is, I could disable it and then get back to booting normally.

Whatever tips and advice you folks can kindly offer would be greatly appreciated.

Thank you.

Nov. 2009 iMac 27, Mac OS X (10.7)

Posted on Apr 16, 2013 2:59 PM

49 replies

JDW1 Author

Level 1

67 points

Feb 18, 2014 5:50 AM in response to iPrist7

It ended well, but it took effort and time on my part.

Because my AppleCare had expired, I had to choose between paying Apple the big bucks to fix my iMac, or buy a new Mac. My wife asked me to investigate a MacBook Pro at the time, but I read numerous reports about issues pertaining to the display, so I really didn't want to substitute one problem with another. What to do!

In the end, I wrote an email to Tim Cook. A week later I received a reply from an executive in Singapore who said their chief engineer would give me a telephone call to confirm the problem. That phone call confirmed the problem in about 5 minutes. I was then scheduled to take my iMac into the Apple store in Nagoya (since I reside in Japan). It took several days, but the swapped out the hard drive, RAM and the video card, all free of charge (I was given an AppleCare special case). But a week later the problem returned and I was back at the Apple Store. They swapped out the video card (with the same exact card) and the display too (also free of charge). I've been using the iMac just fine ever since (and I am typing this message on it too).

That's not to say Mr. Cook's office would offer everyone such a courtesy. I did have AppleCare, albeit recently expired. And I did write a rather lengthy email. I've been a Mac user since the 128k in 1984 and an AAPL investor since 1999 (not having sold a single share since). Yes, I mentioned those things in my email to Mr. Cook. Perhaps it didn't matter. Perhaps it did. But in the end I am grateful for terrific support from Apple.

What are my plans now? Well, my iMac is working great but it is aging. And since Apple swapped my old video card out with the same model video card, chances are this "new" video card will develop the same heat-related death problem a year or two hence. In any case, my wife still covets a MacBook Pro. Perhaps when Broadwell MacBooks come out, I will splurge.

Best wishes.

iPrist7

Level 1

0 points

Feb 19, 2014 3:51 AM in response to JDW1

I allready swapped the Ram and hdd. I now get Lines on screen. The video card might Be The problem, I had some stutter of windows while in Motion prior to Safe mode issue. I have no Apple store in my country. I buy macs from US. So I fix them myself, never encountered such a big damage. If h

Your got slower an ssd gives it a great boost. For me it would Be too much to buy a video card than a screen. I'll just sell it as is.

Apr 15, 2014 11:53 PM in response to JDW1

For anyone who is having same problem, my iMac crashed after a teamviewer session then wouldn't reboot but showed no errors the same and I resolved it by deleting TeamViewer in safe mode and it has all been fine since, may be that my graphics card is on it's way out but it atleast solved the issue for now. So if anyone else is using this app it may be worth a try deleting it.

bgwz

Level 1

8 points

May 10, 2015 12:51 PM in response to JDW1

I was having a similar issue with my old iMac and in searching, luckily came upon this solution. I followed the directions and removed all ATI extensions and placed them into a disabled folder. Now it boots up and I am back to using it, not a moment too soon as I have a big project due in a couple of weeks. My only problem now is that the display will not go to sleep. Did you have the same problem and did you figure out which extension to put back into the system folder? Thank you.

The files I moved out are:

ATINDRV.kext

ATIRadeon.kext

ATIRadeon8500.kext

ATIRadeon8500DVDDriver.bundle

ATIRadeon8500GA.plugin

ATIRadeon8500GLDriver.bundle

ATIRadeon8500VADriver.bundle

ATIRadeon9700.kext

ATIRadeon9700DVDDriver.bundle

ATIRadeon9700GA.plugin

ATIRadeon9700GLDriver.bundle

ATIRadeon9700VADriver.bundle

ATIRadeonDVDDriver.bundle

ATIRadeonGA.plugin

ATIRadeonGLDriver.bundle

ATIRadeonX1000.kext

ATIRadeonX1000GA.plugin

ATIRadeonX1000GLDriver.bundle

ATIRadeonX1000VADriver.bundle

ATIRadeonX2000.kext

ATIRadeonX2000GA.plugin

ATIRadeonX2000GLDriver.bundle

ATIRadeonX2000VADriver.bundle

ATIRNDRV.kext

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iMac Can Only be Booted in Safe Mode (Shift Key held down)