Why is my iMac rebooting overnight?

[ehz1]

I upgraded to Yosemite about a week ago on my work computer. All went well, just did an upgrade from Mavericks on my 27" late 2013 iMac. Before I did the upgrade I did back-up everything, ran disk permissions and verify disk, all was good.

When I go home for the evening I put the computer to sleep. A few days after the upgrade I came into work and the screen was on with only a circle with a line through it. Did a reboot, checked the disk again and all seemed ok. Another day went by and it happened again.

Now it is happening daily, normally it would start up just fine but today it would not. I was able to get it to boot in safe mode and all checks out fine.

What is causing the machine to have to reboot overnight? I don't have auto updates on. Why is it having problems finding the start-up disk? I've done a few searches and have not found anyone with a current system having this issue.

My HD is the 3TB Fusion Drive, did not have any issues until I upgraded which leads me to believe it's a software issue and not hardware but could use some help.

Thanks.

 

[yesjam]

What is causing the machine to have to reboot overnight? I don't have auto updates on. Why is it having problems finding the start-up disk? I've done a few searches and have not found anyone with a current system having this issue.

My HD is the 3TB Fusion Drive, did not have any issues until I upgraded which leads me to believe it's a software issue and not hardware but could use some help.

Thanks.

Sounds to me like a kernel panic. I was having similar issues after upgrading my iMac to Mavericks a year ago. You're on the right track that it is a software issue but it likely isn't a problem with the Yosemite operating system proper, it's more an issue with potential software compatibility and is likely related to preference panes. My advice is to download and run EtreCheck; it will discover and let you know about what software is causing the issue. For example, the problem I ran into was compatibility with the preference pane/software Perian which adds functionality to Quicktime player. Eliminate that software (which might be a bit of a pain but is worth it nonetheless) and the problem will go away. Of course if you can't live without whatever is causing the issue, then you might want to consider reverting to Mavericks. But consider alternative options - in my case, I decided it was way more worth it to use VLC than to deal with Perian causing me issues.

 

[NoBoMac]

Cleaning crew pulling the plug on the machine at night? Have had that happen in the past, so from then on, made sure at least one outlet is not being eaten up.

Or as above, maybe an overloaded powerstrip when cleaners come through?

But why it does not find the drive...

 

[ehz1]

Sounds to me like a kernel panic. I was having similar issues after upgrading my iMac to Mavericks a year ago. You're on the right track that it is a software issue but it likely isn't a problem with the Yosemite operating system proper, it's more an issue with potential software compatibility and is likely related to preference panes. My advice is to download and run EtreCheck; it will discover and let you know about what software is causing the issue. For example, the problem I ran into was compatibility with the preference pane/software Perian which adds functionality to Quicktime player. Eliminate that software (which might be a bit of a pain but is worth it nonetheless) and the problem will go away. Of course if you can't live without whatever is causing the issue, then you might want to consider reverting to Mavericks. But consider alternative options - in my case, I decided it was way more worth it to use VLC than to deal with Perian causing me issues.

Thanks for the advice, I'll give it a try and report back.

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Cleaning crew pulling the plug on the machine at night? Have had that happen in the past, so from then on, made sure at least one outlet is not being eaten up.

Or as above, maybe an overloaded powerstrip when cleaners come through?

But why it does not find the drive...

I'm on a battery back-up and usually the last one to leave. I thought a power surge the first time but to have it happen daily now I don't think we are having power issues since my server will alert me of that. Thanks though!

 

[ehz1]

I ran EtreCheck and all seems to be ok.

The only things that seemed a bit out of the ordinary is this line under Startup Items:

CUDA: Path: /System/Library/StartupItems/CUDA
Startup items are obsolete and will not work in future versions of OS X

And an invalid Launch Daemon: com.logmein.raupdate.plist

I am going to remove Logmein since I don't use it that often. There were no updates for the Cuda driver.

 

[robeddie]

Cleaning crew pulling the plug on the machine at night? Have had that happen in the past, so from then on, made sure at least one outlet is not being eaten up.

Or as above, maybe an overloaded powerstrip when cleaners come through?

But why it does not find the drive...

Real simple solution guys, shut down the mac instead of putting it to sleep if you're not gonna use it for a few hours.

It's better for the machine, and avoids problems like this.