Uncommanded Restarts in Yosemite and El Capitan

[iantunnacliffe]

Macbook Pro Retina 13 inch Late 2013

My Macbook Pro keeps restarting - or sometimes just trying to restart - when it is sleeping.

Typically I find when I return to my Mac after a gap of several hours that it has either restarted itself and is showing the log-in screen or it is showing a message like "Unable to restart because such and such a thing is active". Usually this is because I have an unsaved file open in a Microsoft Office application.

I don't remember this ever happening before I was running Yosemite. This weekend I upgraded to El Capitan and was interested to see if the problem might go away but it hasn't. Opening up the Mac on Monday morning I was presented with the "Unable to restart......" message.

This doesn't happen every time the Mac sleeps. Maybe two or three times a week.

Does anyone have any idea what might be going on?

 

[Ebenezum]

Hard to say without further information.

Open Console app and look logs at the time of the restarts, is there anything unusual or otherwise suspicious?

 

[iantunnacliffe]

Only just saw this reply. Sorry for being dozy. The mysterious restart hasn't happened since Sunday Night/Monday Morning and my console log only seems to go back to Monday afternoon. I'll check it again the next time I get an unwanted restart.

 

[JohnDS]

By the way, do you by any chance have an external USB Western Digital or Hitachi drive attached to your computer? There is a long Apple thread suggesting this might be the root of the problem:

https://discussions.apple.com/thread/5688616?start=60&tstart=0

 

[JohnDS]

The same thread suggests disabling Power Naps in the Energy preferences panel.

 

[JohnDS]

There is also a suggestion that other external USB devices can cause the problem, so if you have any external USB devices attached, try unplugging them overnight.

 

[iantunnacliffe]

I don't use an external USB drive with this Mac but I do occasionally leave a printer/scanner plugged in overnight. The restarts haven't recurred since I posted my first question but I'll check the logs and come back if they do.

 

[iantunnacliffe]

It didn't happen for a few days but then it happened yesterday and again today. Yesterday the restart went through but today it stopped because I had stuff open and unsaved. I have looked at the console but I must admit I am overwhelmed by the amount of stuff in there. I think I can pinpoint the time the crashes happened but what else should I be looking for?

 

[markeeinsik]

this happened to my MBA 2009 once after i updated it to yosemite 10.10.5, but after that. no incident of sudden restart..