iMac waking from sleep

[Wreckie]

Every night I hear few times, when iMac wakes up from sleep, but it isn't going to stay awake, just puts it sleep again after some seconds. What could cause that problem?

 

[gr8tfly]

It might do that if you have "Wake for network access" enabled in the Energy Saver preference pane (in System Preferemces).

 

[Wreckie]

Thanks,
Unchecked that box, will see if makes any difference.

 

[kcossabo]

Every night I hear few times, when iMac wakes up from sleep, but it isn't going to stay awake, just puts it sleep again after some seconds. What could cause that problem?

My Mid-2011 27" iMac will not wake from sleep. Power 10 sec to reboot only way out.

I opened an Apple Care ticket, did P-R Reset and Controller rest. Problem when away, and now it is back.