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A handful of Air Display users on Mac OS X have reported seeing a blue screen after updating the Air Display Connect software. The main screen turns blue, and the Finder never appears. To most users, the Mac appears to be unusable. This is a pretty serious problem. Fortunately, (1) it has only affected very few users, and (2) there’s an easy workaround.
The problem is simply that Mac OS X occasionally corrupts its kernel extension cache. If you boot to a blue screen, you can recover with these two steps:
- “Safe Boot” your Mac: Select > Restart, then press and hold the Shift key immediately after you hear a tone. Release when the Apple logo appears.
- Restart again.
All should now be fine and you should not see the blue screen again.
UPDATE: We isolated the bug and implemented a workaround in Air Display Connect version 1.6.5. If you’re running Air Display on Mountain Lion, please Check For Updates. All will be well.We discovered a fascinating obscure bug in Mountain Lion. Fortunately there’s an easy workaround. Here’s the bug:
- Sleep your Mac (either explicitly or by closing a laptop).
- Turn off all of your Bluetooth devices.
- Wake your Mac.
- Watch helplessly as your Mac goes into a Kernel Panic.
- Don’t do that. At least not in that order.
If you turn off your Bluetooth devices before sleeping, you’ll be fine. If you don’t turn off the Bluetooth devices at all, you’ll be fine. It’s only if you turn off the devices while the Mac is sleeping that this happens.
Some people have also noticed that they can make the kernel panic go away by uninstalling certain third-party kernel extensions. Among them is Air Display. But don’t remove Air Display! It’s awesome!
We’re expecting that Apple will fix this soon. It’s probably related to the half-finished work on Power Nap, which still (as of right now anyway) isn’t enabled on the Retina MacBook Pro. Since the bug appeared in the Mountain Lion GM, and since Power Nap still isn’t really finished, we’re guessing that the bug is the results of some stressful late-night code thrashing in Cupertino, and that Mac OS X 10.8.1 will address this.
We have more information. The above description is accurate if you have this option enabled on your Mac: Allow Bluetooth Devices To Wake Your Computer. It’s on by default. If you turn that option off (in System Preferences > Bluetooth > Advanced), the system will kernel panic even if you don’t turn off the Bluetooth devices.
So if the above workaround isn’t effective for you, make sure this option is turned on.
If you’re at Apple, you can see more details at rdar://11977211.