- Joined
- Jul 28, 2016
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- 32
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- Location
- Turin, Italy
- Your Mac's Specs
- Mac Mini 2014 - 8GB Ram, 512GB SSD - macOS 10.12
I wanted to share this (partial) solution I found about a problem many people have: all of a sudden, the iMac (or other Mac) shows vertical lines on screen, and it freezes during boot.
I didn't find this solution anywhere else, that's why I thought someone might be interested.
- The Mac: iMac Early 2008 24" with ATI 2600 HD video card, and OSX 10.9.
- The problem: the iMac's screen shows vertical lines (mine are red) as soon as it's switched on; the startup "bong" sounds normally, the boot goes on but, after a while, it just freezes on the light gray screen with dark gray Apple logo.
- The (partial) solution: remove all the video card drivers. This way it boots fine.
* My reasoning
The graphic card was most likely damaged but, since the screen showed the boot screen, it wasn't dead.
The iMac booted fine in Recovery mode and Safe mode (although always with those lines), so I knew it was still working.
I thought maybe the video drivers were corrupted, so I reinstalled OSX 10.9. That didn't solve anything.
I asked myself: Why is it booting ok in Safe Mode? Safe mode doesn't load most drivers. So I thought "Maybe the video drivers are conflicting with the damaged video card, hence the freeze during startup. If that's true, if I remove those drivers, the iMac should boot normally". And that worked!
* My solution
- Boot in Safe mode (press the Shift key until you see OSX loading)
- Open "/System/Library/Extensions" folder (on your startup disk)
- Move all the kext (kernel extensions) files pertaining to your video card to another folder (mine is an ATI 2600, hence I moved all the AMD and ATI files)
(the step above actually makes a copy of those file, it doesn't move them. That's ok, keep those new files for backup).
- Delete those same files from the original folder; OSX asks for the system password (the same you insert at startup)
- Open Terminal: sudo touch "/System/Library/Extensions" (it asks for password); close Terminal
- In Finder, open "System/Library/Caches/" folder
- Delete "com.apple.kext.caches" folder (it asks for password)
- Restart your Mac
Your Mac should now boot normally - although those pesky lines won't go away, of course (since the hardware is still damaged). The screen redraw could be slower than usual, but for most operations it should be fine. Most apps will work as usual.
This way you can make your backups, search for solutions, and do any stuff you need. And if those lines do not bother you that much, you can even go on using your Mac as it is! :-D
PS: I know the "real" solution is to replace or resolder (reflow) the video card. But on a 9 years old iMac, I thought it wasn't worth the trouble. YMMV
I didn't find this solution anywhere else, that's why I thought someone might be interested.
- The Mac: iMac Early 2008 24" with ATI 2600 HD video card, and OSX 10.9.
- The problem: the iMac's screen shows vertical lines (mine are red) as soon as it's switched on; the startup "bong" sounds normally, the boot goes on but, after a while, it just freezes on the light gray screen with dark gray Apple logo.
- The (partial) solution: remove all the video card drivers. This way it boots fine.
* My reasoning
The graphic card was most likely damaged but, since the screen showed the boot screen, it wasn't dead.
The iMac booted fine in Recovery mode and Safe mode (although always with those lines), so I knew it was still working.
I thought maybe the video drivers were corrupted, so I reinstalled OSX 10.9. That didn't solve anything.
I asked myself: Why is it booting ok in Safe Mode? Safe mode doesn't load most drivers. So I thought "Maybe the video drivers are conflicting with the damaged video card, hence the freeze during startup. If that's true, if I remove those drivers, the iMac should boot normally". And that worked!
* My solution
- Boot in Safe mode (press the Shift key until you see OSX loading)
- Open "/System/Library/Extensions" folder (on your startup disk)
- Move all the kext (kernel extensions) files pertaining to your video card to another folder (mine is an ATI 2600, hence I moved all the AMD and ATI files)
(the step above actually makes a copy of those file, it doesn't move them. That's ok, keep those new files for backup).
- Delete those same files from the original folder; OSX asks for the system password (the same you insert at startup)
- Open Terminal: sudo touch "/System/Library/Extensions" (it asks for password); close Terminal
- In Finder, open "System/Library/Caches/" folder
- Delete "com.apple.kext.caches" folder (it asks for password)
- Restart your Mac
Your Mac should now boot normally - although those pesky lines won't go away, of course (since the hardware is still damaged). The screen redraw could be slower than usual, but for most operations it should be fine. Most apps will work as usual.
This way you can make your backups, search for solutions, and do any stuff you need. And if those lines do not bother you that much, you can even go on using your Mac as it is! :-D
PS: I know the "real" solution is to replace or resolder (reflow) the video card. But on a 9 years old iMac, I thought it wasn't worth the trouble. YMMV
