iMac constantly wakes from sleep

[Aragornii]

I have an Imac running ML that is my main computer. It has iTunes which serves to my apple tv's and iphone backups, etc.

Problem is it won't stay asleep even when i'm not accessing it via apple tv. i.e., it will sleep for a few minutes then the screen comes back on.

Any idea what is causing it to continually wake all the time? It's in a guest room so when we have people staying in there we just have to turn the computer off.

 

[GGJstudios]

For sleep issues, you may find some useful ideas here:

• Determine why your Mac wakes up from sleep
• OS X Mountain Lion: If your Mac won’t go to or stay in sleep
• Mac OS X: Why your Mac might not sleep or stay in sleep mode
• One sleep problem caused by printers - solved ... and another
• If your Mac isn't sleeping properly and you have gfxCardStatus installed, try uninstalling it.

 

[Ledgem]

GGJ's links will probably solve it for you and probably have the solution that I'm about to suggest, but I didn't go through his links. I had a similar issue with one of my computers - it would wake about once every hour or so but, being a laptop with the lid closed and no external monitors connected, it would go to sleep shortly after. The solution was to disable "wake for network access," a checkbox that can be found in the "Energy Saver" preferences in the System Preferences.

I can't explain why it worked, considering that all of my computers could be "sleeping" and that one would still "wake up." None of my iOS devices were trying to access it, as far as I know, and it's an older system that isn't compatible with Apple's newer "sleep updates" features. Regardless, after unchecking it the system hasn't come out of sleep without opening the lid since.

 

[Aragornii]

That first link was very interesting. I ran the terminal command it suggested, and saw that almost exactly every 12 minutes my computer is waking from sleep due to "EHC1", which apparently is a bluetooth or USB device. will start unplugging things and see what works.

For sleep issues, you may find some useful ideas here:

• Determine why your Mac wakes up from sleep
• OS X Mountain Lion: If your Mac won’t go to or stay in sleep
• Mac OS X: Why your Mac might not sleep or stay in sleep mode
• One sleep problem caused by printers - solved ... and another
• If your Mac isn't sleeping properly and you have gfxCardStatus installed, try uninstalling it.

 

[Aragornii]

Very curious. unplugged all USB and turned off bluetooth. still waking regularly due to EHC1.

 

[Samuriajackon]

Very curious. unplugged all USB and turned off bluetooth. still waking regularly due to EHC1.

Interesting, do you have anyone else on your network? Do you have any Network items that might be "wakeing" your Mac to do backups or anything?

I had a Laserjet printer that would wake my Windows machines up long ago...