February 27, 2008 12:21 PM PST

Mac OS X 10.5.2 Special Report: Wake-from-sleep issues (inadvertent restarts, more)

by CNET staff

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There exist a range of wake-from-sleep issues under Mac OS X 10.5.2 -- most notoriously a probem where an attempted wake results in a restart. Users are also reporting other problems, including a blank screen on wake-from-sleep.

As suggested in our tutorial, some of these issues may be Bluetooth related. Try turning off the option (located in the Keyboard/Mouse pane of System Preferences) to allow Bluetooth devices to wake your Mac.

Other readers found they needed to disable Bluetooth entirely:

"I've also had severe wakeup-from-sleep issues. Completely black screen (no backlight) - and no way to get back except a hard reset - much like reader Joe Lorek. I've at last traced it to bluetooth. If I switch bluetooth off, then restart, then all is well (I can wakeup as I please when I please). After switching it on, if I sleep the machine, the wakeup issue restarts."

There is also an issue in which external displays do not come on at all while the notebook's lid is closed and will not wake up when keys on an external keyboard or buttons on an external mouse are pressed.

One MacFixIt reader describes this issue:

"When I wake my MacBook Pro in closed-lid mode it shows the desktop picture on the external screen and then goes right back to sleep. If I then wake it again, the same thing will happen all over again. AC power is connected and the mouse/KB are working too so that's not the cause of the problems. Somehow the MBP seems to constantly want to go back to sleep right after it wakes up."

Fixes

Shut lid immediately Since this problem generally occurs on notebooks with external displays, one workaround involves the following: Press the power button on your Mac (with external display connected) then immediately shut the lid. Your Mac will continue booting and the external display should show the proper resolutions.

Now, open your Mac's lid and go to System Preferences, then select "Displays" and press the "Detect Displays" button. You may now be able to boot normally with all previously available resolutions.

Reset SMC Instructions for:
MacBook and MacBook Pro

MacFixIt reader Philip Chadwick writes:

"An SMC reset solved the problem on my MBP 2.4GHz."

"I use a Samsung Syncmaster 191t as a desktop expander to my MacBook Pro. Two days ago, I used my MacBook Pro to drive a projector, and when I reconnected the Samsung, the screen resolution for the Samsung, 1280x1024, was missing from the list. Spent an hour and $50 with Apple support. After a PRAM reboot (?) and lots of time with disk utility, it is finally working again..."

To reset PRAM/NVRAM, shut down your Mac, then start it back up while immediately holding the following keys: Command, Option, P and R. Hold the keys down until the computer restarts and you hear the startup sound for the third time.

Delete a specific cache We've also received word that deleting the following, specific cache file:

/System/Library/Extensions/Caches/com.apple.kext.info

can resolve this issue. [Thanks Fredrik]

Downgrading to Mac OS X 10.5.1 or removing the Graphics update If this issue proves too disruptive to your workflow, follow our tutorial on reinstalling the system then update to Mac OS X 10.5.1. We've received some reports that upgrading to 10.5.2 but refraining from installing the Leopard Graphics Update alleviates this issue, indicating that the graphics update is to blame.