iMac wakes itself up, then puts itself back to sleep
My iMac constantly wakes itself from sleep. The problem seems to have started around the time that I upgraded to Yosemite. If I leave the computer in sleep mode overnight, it will happen dozens of times throughout the night. The computer wakes up, but the monitor never comes on. I hear the hard drive spin up, I see my mouse’s LED turn on, then after a few seconds it goes back to sleep.
I have tried everything in this KB article (https://support.apple.com/en-gb/TS5357) with no luck. I have done SMC and PRAM resets with no luck. I’ve tried unplugging all USB devices prior to sleep in case one of them was waking the machine, with no luck. I have no Bluetooth devices, and Bluetooth is turned off. “Wake for network access” is turned off. I have no scheduled power or wake/sleep events. I have no file or device sharing enabled.
If I do a “wake reason” terminal command, I have page after page of the following message with varying timestamps: “Mar 28 11:45:20 iMac kernel[0] <Notice>: Wake reason: RTC (Alarm)” The info I’ve found about this says, “Real Time Clock Alarm, is generally from wake-on-demand services like when you schedule sleep and wake on a Mac via the Energy Saver control panel. It can also be from launchd setting, user applications, backups, and other scheduled events.” Again, I have no scheduled wake settings, “wake for network access” it off, and I have no applications that should be waking the computer.
I’m at my wits’ end with this problem. At this point, the only thing I can think to do is a full reinstallation of OS X, but I’d really rather not have to go that far. Any suggestions?
Specs:
iMac (20-inch, Mid 2007)
OS X 10.10.2
Processor: 2.4 GHz Intel Core 2 Duo
Memory: 4 GB 667 MHz DDR2 SDRAM
Graphics: ATI Radeon HD 2600 Pro 256 MB
iMac (20-inch Mid 2007), OS X Yosemite (10.10.2), 2.4 GHz Intel Core 2 Duo, 4 GB RAM