Mac rebooting randomly

[graham.mess]

Hi,

Im having issues with my work machine. It seems to reboot quite regularly for some reason. I do a lot of motion graphics and video editing so have a feeling it may be to do with that.
Machine details are:
8 GB 1867 MHz DDR3

Here are the last messages in the diagnostics just before the reboot:
22/08/2016 09:47:14.705 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:14.705 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:16.209 Safari[855]: KeychainGetICDPStatus: keychain: -25300
22/08/2016 09:47:16.209 Safari[855]: KeychainGetICDPStatus: status: off
22/08/2016 09:47:16.853 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:16.853 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:16.855 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:16.855 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:22.757 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:22.757 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:22.767 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:22.767 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:22.788 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile header length is greater than data length.
22/08/2016 09:47:22.788 com.apple.WebKit.WebContent[930]: ImageIO: readICCData Embedded profile signature is not valid.
22/08/2016 09:47:31.431 Safari[855]: KeychainGetICDPStatus: keychain: -25300
22/08/2016 09:47:31.431 Safari[855]: KeychainGetICDPStatus: status: off
22/08/2016 09:47:41.423 Safari[855]: KeychainGetICDPStatus: keychain: -25300
22/08/2016 09:47:41.423 Safari[855]: KeychainGetICDPStatus: status: off

Any help or confirmation would be great thanks.

Graham

 

[keysofanxiety]

Please could you confirm your iMac model? Year, size, etc.

 

[graham.mess]

iMac (Retina 5K, 27-inch, Late 2015)
3.2 GHz Intel Core i5
8 GB 1867 MHz DDR3
AMD Radeon R9 M390 2048 MB

Thanks

 

[BrianBaughn]

One possible cause of crashes is RAM that has gone bad (or may not be seated properly). Test the iMac with one stick of RAM at a time.

 

[joema2]

Hi,

Im having issues with my work machine. It seems to reboot quite regularly for some reason. I do a lot of motion graphics and video editing so have a feeling it may be to do with that...

I had a similar problem on my 2015 top-spec iMac 27. Apple eventually traced it to a defective logic board. If you call Apple support they will have you try a bunch of things such as:

Apple Diagnostics: https://support.apple.com/en-us/HT202731
Resetting NVRAM: https://support.apple.com/en-us/HT204063
Resetting SMC: https://support.apple.com/en-us/HT201295
Re-installing OS X: https://support.apple.com/en-us/HT204904

Those are all reasonable things to try and it might fix the problem. If it doesn't at the Apple Genius Bar they have more robust diagnostics they can run, some of which may require overnight testing.

 

[graham.mess]

Thanks joema2, I cleared all my files that I didn't use and done a full clean up of the system and freed up space. Since then it hasn't crashed (fingers crossed), and that has been few days.

I think it was literally RAM and space issues. Im looking into getting 2x4GB slots to go into the empty slots.

Thanks

 

[joema2]

Thanks joema2, I cleared all my files that I didn't use and done a full clean up of the system and freed up space. Since then it hasn't crashed (fingers crossed), and that has been few days.

I think it was literally RAM and space issues. Im looking into getting 2x4GB slots to go into the empty slots.

Thanks

That is possible. However in my case after I did all those steps including reinstalling OS X, it went away for a few weeks than started again. The nature of some hardware faults is they are unpredictable and inconsistent. If it never happens again on your Mac, great. If it does eventually happen, don't be too surprised.

At the Genius bar they have a *lot* of additional diagnostics they can run, some requiring overnight or even multi-day stress. I was afraid they wouldn't find anything since I had run Apple Diagnostics many times plus various other stress tests like Prime95, Furmark, etc. However they found it during an overnight stress test. Don't hesitate to take it in if necessary.