I have an iMac (Retina 5K, 27-inch, Late 2015) with MD Radeon R9 M395 2 GB graphics card. I have the 27" Apple monitor as a second screen. With Big Sur, the iMac crashes EVERY TIME it goes to sl;eep, and reboots. What's going on?

I have an iMac (Retina 5K, 27-inch, Late 2015) with MD Radeon R9 M395 2 GB graphics card. I have the 27" Apple monitor as a second screen. With Big Sur, the iMac crashes EVERY TIME it goes to sleep and reboots. What's going on?





iMac Line (2012 and Later)

Posted on Jan 30, 2021 8:44 AM

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Question marked as Top-ranking reply

Posted on Jan 30, 2021 11:37 AM

First some education:


The best antivirus, cleaning app, and overall maintenance app for Mac OS is Mac OS itself. All you need to do with Mac OS to keep it secure and running well is to keep it up-to-date and do periodic (about 1x per week) restarts. Other than that, leave it alone. Adding third party antivirus, cleaning, security and other types of maintenance apps to Mac OS adds no additional level of security. The only thing these apps do is have the opposite affect users want. They make Mac OS slow, unstable, generate odd behavior (much like you are experiencing) and make Mac OS appear buggy. 

 

Please locate the developers uninstall instructions for CleanMyMac and follow to the letter. Next download the free version of FindAnyFile and use it to find and put anything with the names:


  • CleanMyMac
  • MacPaw


into the Trash and then empty the Trash. Using Malwarebytes is okay and you should use it as your report indicates you downloaded some adware, so run Malwarebytes and see if it finds anything.


Then restart in Safe Mode per the directions in Use safe mode to isolate issues with your Mac and then restart normally. 


Finally, I see no evidence that you backup this computer which is shortsighted and a 100% guarantee you will lose data. At the very least you should be backing up using Time Machine. Your will need a good quality External Hard Disk such as a OWC Mercury Elite Pro that is about 2-3 times the capacity of the data you have on your computer or just get a 3TB model.


6 replies
Question marked as Top-ranking reply

Jan 30, 2021 11:37 AM in response to 2015-iMac-Rebooting

First some education:


The best antivirus, cleaning app, and overall maintenance app for Mac OS is Mac OS itself. All you need to do with Mac OS to keep it secure and running well is to keep it up-to-date and do periodic (about 1x per week) restarts. Other than that, leave it alone. Adding third party antivirus, cleaning, security and other types of maintenance apps to Mac OS adds no additional level of security. The only thing these apps do is have the opposite affect users want. They make Mac OS slow, unstable, generate odd behavior (much like you are experiencing) and make Mac OS appear buggy. 

 

Please locate the developers uninstall instructions for CleanMyMac and follow to the letter. Next download the free version of FindAnyFile and use it to find and put anything with the names:


  • CleanMyMac
  • MacPaw


into the Trash and then empty the Trash. Using Malwarebytes is okay and you should use it as your report indicates you downloaded some adware, so run Malwarebytes and see if it finds anything.


Then restart in Safe Mode per the directions in Use safe mode to isolate issues with your Mac and then restart normally. 


Finally, I see no evidence that you backup this computer which is shortsighted and a 100% guarantee you will lose data. At the very least you should be backing up using Time Machine. Your will need a good quality External Hard Disk such as a OWC Mercury Elite Pro that is about 2-3 times the capacity of the data you have on your computer or just get a 3TB model.


Feb 1, 2021 9:07 AM in response to mikewilson.255

New troubleshooting (by me) reveals that my iMac only crashes when my external monitor is plugged in! With the external UNplugged the iMac NEVER crashes. I tested this multiple times, and the results are the same. I have had this Apple 27" monitor for about 4 years and no problems. This appears to be happening since Big Sur upgrade!!


I tried to paste a screenshot of my Time Machine, and this chat app must not want data other than text. The output from TM showed the following:

  • I am using a 4T drive
  • The drive has 1.99 T available
  • Oldest backup is Aug 11, 2020
  • Latest backup was today 30 minutes ago
  • Next backup is in less than 30 mins



Jan 30, 2021 8:46 AM in response to 2015-iMac-Rebooting

We can see if there are any obvious issues if you post an EtreCheck report of your system. Please do the following:


Please navigate to the Mac App Store or navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.


When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 


For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211


This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

I have an iMac (Retina 5K, 27-inch, Late 2015) with MD Radeon R9 M395 2 GB graphics card. I have the 27" Apple monitor as a second screen. With Big Sur, the iMac crashes EVERY TIME it goes to sl;eep, and reboots. What's going on?

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