iMac Core Duo (Early 2006) (#4): Sporadic blue screens

We're beginning to investigate an issue reported by some iMac Core Duo users where the Mac OS X blue screen (symptomatic of a logout) occurs at random intervals, returning the user to the normal working environment after each incident.

"I recently got the 20" Intel iMac, which is a beautiful machine. But I'm experiencing an odd problem. Intermittently, the screen will momentarily freeze, with no input possible. Then it goes completely blank blue. Then, in anywhere from a second, to several seconds comes back, with everything as it was. Weird. I'm not sure if it's an incompatibility. The only 3rd party Preference Pane I'm running is USB Overdrive (which I'd hate to turn off 'cause my Logitech mouse needs the buttons). Intermittently is rather unpredictable. It tends to happen over and over when it begins, but then it stops and everything's peachy for long periods.

"It could be something with the Energy Saver Preferences. I allowed transfer of preferences from my older eMac, which was a mixed blessing; lots to throw away. And the Energy Saver preferences were weird, very short time intervals. So I changed all that. Anyway, obviously I haven't tried hard to solve the problem, hoping that someone smarter has it, and has solved it (or not)."

If you are experiencing a similar issue, please let us know.

Feedback? Late-breakers@macfixit.com.

Previous coverage:

• iMac Core Duo (Early 2006) (#3): Safe sleep available; Problems with iSub
• iMac Core Duo (Early 2006): Problems with installing Intel Mac OS X on FireWire drives; solution
• Apple unveils new iMac with Intel Core Duo: 2-3X faster than iMac G5, shipping today

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