System keeps waking from sleep every 2 hours
Since Yosemite update, system keeps waking from sleep approx. every 2 hours. It goes back to sleep on its own but keeps waking up again. I have "wake for network access" in System Preferences turned off. Here are samples of the console messages:
10/19/14 1:02:43.000 AM kernel[0]: Wake reason: RTC (Alarm)
10/19/14 1:02:43.000 AM kernel[0]: RTC: Maintenance 2014/10/19 08:02:43, sleep 2014/10/19 06:14:45
10/19/14 3:00:41.000 AM kernel[0]: Wake reason: RTC (Alarm)
10/19/14 3:00:41.000 AM kernel[0]: RTC: Maintenance 2014/10/19 10:00:41, sleep 2014/10/19 08:12:51
I have no idea what "Wake reason: RTC (Alarm)" means. Any help would be appreciated.
iMac, OS X Yosemite (10.10), 2011 iMac Intel Core i5 12GB RAM