mountain lion hanging when wake from sleep

mountain lion hanging when wake from sleep

Mountain Lion won't wake up after an extended sleep
The current workarounds are:
Disable hibernate mode.
Disable standby mode.

Mountain Lion can’t Wake Up from Slumber
SEPTEMBER 5, 2012

Troubleshooting system sleep in OS X
1. Disconnect or disable peripherals
2. Reset the power manager
3. Remove the sleep image file
$ sudo rm /private/var/vm/sleepimage