June 7, 2006 2:06 PM PDT

MacBook Pro Special Report: Not sleeping properly, still "on" with lid closed

by CNET staff

Some MacBook Pros not go to sleep properly, remaining on but inactive (blank screen) when the lid is closed or sleep is manually invoked.

In these cases, you will notice that the MacBook Pro's sleep indicator light does not pulse on and off, the fan remains on and the unit extremely hot even though the lid is closed. Battery power also depreciates rapidly.

MacFixIt reader Andrew Springer writes:

"I put my system to sleep and placed it in my bag before leaving the office, when I got home the MacBook was red hot with the fan spinning. I was unable to wake the system and had to shut it down by holding down the power key. It restarted fine, but I've wondered ever since if this caused the problem.

"This happened again just yesterday. In this case I put my computer to sleep, then opened it up again just briefly (less than 5 seconds) and shut it again. The system didn't appear to wake-up, but 30 minutes later when I removed it from the bag the computer was very very hot again with the fan spinning. Again I had to force the computer to shutdown before I could use it. Battery seems OK right now, I'll keep you posted if that changes.

"It's a bit of a concern that it appears that if you quickly open the screen and then close it (accidentally or on purpose) that the computer may wake, but not sleep again."

To reiterate, some potential fixes for this issue:

Check Energy Saver settings Turning off all energy saving options in the Energy Saver pane of System Preferences can resolve this issue for some MacBook Pros.

This can be accomplished by entering the Energy Saver pane of System Preferences, clicking on the "Options" tab, then unchecking all options, including:

Wake when the modem detects a ring

Wake for Ethernet Network administrator access

Restart automatically after a power failure

Check for problems caused by external devices In some cases, errant USB or FireWire devices can cause problems with sudden power-offs. Try disconnecting all such devices and see if the problem persists.

Reset PMU Some users have been able to resolve the problem by performing a PMU reset. Instructions are as linked:

PowerBook and iBook

MacBook Pro

Resetting NVRAM via Open Firmware (PowerPC portables only) A number of users report that resetting NVRAM resolves similar issues. In order to perform this process, hold down the Command, Option, P and R keys at startup until you hear three startup chimes.

Disabling Network activity before sleep Terminating all network activity -- in some cases necessitating a power-down of the AirPort card or disconnection of an Ethernet cable -- is, in some cases, particularly effective at eliminating the "blank screen on wake-up" issue.

Other fixes You may want to try some of the workarounds listed in our tutorial "Dealing with Wake-from-sleep issues."