I purchased a new iMac (2012) last week and used the Migration Assistant to move all my apps and data from my old iMac (2007). Everything went well until yesterday when my new iMac began freezing up after being awakened from sleep. At times it won't shut down until i force close it using the power button. I never had this problem with the old iMac. What could be wrong
iMac, OS X Mountain Lion (10.8.1)
SInce you are on 10.8.1 it looks like you did not apply the update.
I am up to date with ML.
I believe the OP's machine shipped with 10.8.2 however this does not address his problem. The first thing I'd try is a SMC and PRAM resets. Please do both resets please follow the detailed instructions in:
https://discussions.apple.com/docs/DOC-3603
I would also recommend restarting Safe Mode, this will clear some caches. It's possible one or more is corrupt:
http://support.apple.com/kb/HT1455
If these action do not solve your issue then please call AppleCare, you have 90 days of free telephone support. This would be the ideal opportunity to use it.
What all USB devices are connected?
One way to test is to Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, Test for problem in Safe Mode...
PS. Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive
Reboot, test again.
If it only does it in Regular Boot, then it could be some hardware problem like Video card, (Quartz is turned off in Safe Mode), or Airport, or some USB or Firewire device, or 3rd party add-on, Check System Preferences>Accounts>Login Items window to see if it or something relevant is listed.
Check the System Preferences>Other Row, for 3rd party Pref Panes.
Also look in these if they exist, some are invisible...
/private/var/run/StartupItems
/Library/StartupItems
/System/Library/StartupItems
/System/Library/LaunchDaemons
/Library/LaunchDaemons
My new iMac (2012) freezes after awakening from sleep and won't shut down
