Mac does not sleep automatically in Lion! My Macbook Pro will not sleep even though it is set in System Preferences &#x2192; Energy Saver.


I do not have any sharing options enabled (System Preferences &#x2192; Sharing).
I do not have "Wake for network access" enabled (System Preferences &#x2192; Energy Saver).
It does not matter if the Mac is connected to a power source.
I've reset the SMC and the PRAM, but this did not help.


I'm running OS X 10.7.3.
Another safe boot revealed that the auto sleep mode actually is working. I believe that it would probably have worked the last time I've tried it as well  - but, since the sleep occurs several minutes later than the time defined in the Energy Saver settings, I did not notice this.

What about the 'normal' boot? 

I've basically tested the auto sleep with all my menu extras enabled one by one, because the iotop command mentioned by @StuWilson didn't show anything helpful to me. As it turns out the menu extra Stack Exchange Notifier caused insomnia.