Mac Pro keeps waking itself up and going back to sleep

Philocetes

macrumors regular
Original poster
Sep 23, 2016
106
34
My 2012 mac pro seems to have insomnia. When its sleeping it seems every 5-10 minutes it wakes itself up and cycles the superdrive--presumably to see if there is some disk in it, and goes back to sleep. I think I cured this on my 2010, but I can't remember how I cured it.

I have used lingon and don't see any apps that have timed wake-ups, so my chief suspect right now is the time machine backup. Surely the time machine knows to leave it alone when its sleeping.

Any thoughts? Its not in and of itself a big deal, but when this sort of thing happens, I wonder about some sort of malware phoning home or some such.

PS. Just turned off 'wake on lan', maybe that's it.
 

ActionableMango

macrumors G3
Sep 21, 2010
9,263
6,251
Any thoughts? Its not in and of itself a big deal, but when this sort of thing happens, I wonder about some sort of malware phoning home or some such.
What does the log say? Every wake event is logged with the reason why it woke.

syslog |grep -i "Wake reason"
 
Last edited:

Philocetes

macrumors regular
Original poster
Sep 23, 2016
106
34
This is just a sample. I think I had this when I looked into this on my other computer--I believe this means real time clock alarm. Looking at this more closely, it looks like it didn't wake from last night when I put it to sleep until this morning. Maybe turning off wake on lan took care of the problem. I can check again later today or tomorrow. Thanks for reminding me of the log/grep command.


Oct 11 13:26:29 MacProMark kernel[0] <Notice>: Wake reason: RTC (Alarm)
Oct 11 13:35:39 MacProMark kernel[0] <Notice>: Wake reason: RTC (Alarm)
Oct 11 13:44:49 MacProMark kernel[0] <Notice>: Wake reason: RTC (Alarm)
Oct 11 13:53:59 MacProMark kernel[0] <Notice>: Wake reason: RTC (Alarm)
Oct 11 14:03:09 MacProMark kernel[0] <Notice>: Wake reason: RTC (Alarm)
Oct 11 14:12:19 MacProMark kernel[0] <Notice>: Wake reason: EHC1
Oct 11 19:26:37 MacProMark kernel[0] <Notice>: Wake reason: EHC1
Oct 11 20:47:10 MacProMark kernel[0] <Notice>: Wake reason: EHC1
Oct 12 06:44:24 MacProMark kernel[0] <Notice>: Wake reason: EHC1
 

ActionableMango

macrumors G3
Sep 21, 2010
9,263
6,251
RTC is scheduled services like any wake or sleep times you've manually set up. It can also be energy saving settings. But the log does not show consistent times, so I'm not sure what's going on there.

EHC is the enhanced host controller and means that either a USB or bluetooth device is waking the computer up, like if you press a key on the keyboard or move the mouse.

I've found that even minute movements from a high-resolution USB mouse can wake the computer up. For example when a cat jumps on the table even that small vibration will be detected by the mouse as movement and wake the computer up. This started happening to me when I switching to a gaming mouse that has very high resolution.

EDIT:
I think your suspicion may be correct, if you have other Apple devices on your network. Wake on LAN will purposely wake the computer up from time to time for Bonjour proxy services:
https://support.apple.com/en-us/HT201960
(see the first bullet item)
 
Last edited:
  • Like
Reactions: Philocetes

Philocetes

macrumors regular
Original poster
Sep 23, 2016
106
34
Thanks, Mango. Looks like a good explanation. As I noted, the machine spins up the superdrive which would make sense if it was doing a census of potential new data to share.

PS: I checked again yesterday and the RTC wakeups are completely gone--thanks again for the suggestion. It was definitely the wake on lan. Could be bonjour as someone suggested, or who knows what sort of traffic my home router/switch might be sending around every so often.
 
Last edited: