1 Reply Latest reply: May 31, 2013 12:53 PM by Eric Root
mc_razza Level 1 (0 points)



As the title says, my early 2008 iMac is having sleep issues. Specifically, when I put the display to sleep (via a Hot Corner or via Control+Shift+Eject) I have recently noticed that my imac goes to sleep anywhere between 2 minutes and 5 minutes AFTER display went to sleep but BEFORE its set time of 10 minutes in System Preferences>Energy Saver. Both the "Computer sleep" and "Display sleep" sliders are set at 10 minutes by default. I experimented extending the sliders out to 20, 30 and 60 minutes and replicated teh same results ie. computer going to sleep 2-5 minutes after I put the display to sleep. The "Put hard disk to sleep", "Allow power button to put the computer to sleep" and "Start up automatically after a power faliure" boxes are normally checked and I tested to see if unchecking these boxes makes any difference but found that it had not.


This problem is really annoying me because everytime I leave the computer for a short break and come back 1, 2, 5 or so minutes later I discover the computer fast asleep. It's even more annoying when I set a program or a CPU-heavy task to run late at night, turn the display off to save power and wake up the next day to discover that about 5 minutes' worth of work had been completed before the computer went to sleep HOURS ago.


So my question is this: why is the computer going to sleep so early when I set it to go to sleep much later?


Your comments and suggestions are welcome and any response would be most greatly appreciated.


My sincere thanks in advance.



iMac (24-inch Early 2008), OS X Mountain Lion (10.8.3)
  • Eric Root Level 9 (50,612 points)

    Try deleting the com.apple.systempreferences.plist.


    You need to look in your user Library/Preferences for the .plist. Hold down the option key while using the Finder Go To Folder command. Enter ~/Library/Preferences.  Move the .plist to your desktop.


    Restart and test. If it works okay, delete the plist(s) from the desktop. You will need to reset your system preferences.

    If the same, return the .plist(s) to where you got them from, overwriting the newer ones.

    If you prefer to make your user library permanently visible, use the Terminal command found below.


    You might want to bookmark the command. I had to use it again after I installed 10.8.2. I have also been informed that if you drag the user library to Finder it will remain visible.


    If that doesn't work, try setting up another admin user account to see if the same problem continues. If Back-to-My Mac is selected in System Preferences, the Guest account will not work. The intent is to see if it is specific to one account or a system wide problem. This account can be deleted later.


    Isolating an issue by using another user account


    If the problem is still there, try booting into the Safe Mode.  Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal. This will reset some caches, forces a directory check, and disables all startup and login items, among other things. If the system operates normally, there may be 3rd party applications which are causing a problem. Try deleting/disabling the third party applications after a restart by using the application unistaller. For each disable/delete, you will need to restart if you don't do them all at once.


    Safe Mode


    Safe Mode - About


    General information.


    Isolating issues in Mac OS X


    Troubleshooting Permission Issues



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