Mac OS Big Sur Freezing fix



MacOS 11 is designed to run smoothly but it is not unusual that this new Mac version causes freezing followed by a sudden system restart on some computers.

Some Big Sur users have been reporting a problem where the whole OS spontaneously freezes and then reboots on its own after a minute or so.

As per the reports, this Big Sur freezing problem often occurs in a loop a little after login but there are cases where it happens when the user attempts to do some basic task such as launching a program or opening a new tab in safari.

The system freezing, in general, is an issue that is related to the performance, thus, it may be beneficial to improve the overall performance in order to fix this problem. 

In this post, we have come up with some suggestions that might be able to help you solve the Big Sur Freezing issue. Giving them a try might be a good idea if you are looking for a DIY solution:

Big Sur Freezing Solution

  1. Start with the good old system restart. Shut your Mac computer down, wait for a few seconds and then switch it on again.
  2. Another thing that might help is to disconnect all peripheral devices and check if you are still experiencing the Big Sur Freezing issue.
  3. A possible fix is to reset PRAM and NVRAM in your Mac and see if the issue persists.
  4. Reset the System Management Controller (SMC) could be another soultion to your problem.
  5. Reset the sound preferences and the Startup Disk. Sometimes, these preferences might be causing system issues.
  6. Launch the computer in Safe Mode and see if you are experiencing the same Big Sur Freezing issue this way. Then, restart the Mac computer normally.
  7. Check your Mac with Apple Hardware Test to detect if there are hardware issues that you don’t know of.

Did we help? If yes, a thanks in the comments would go a long way to warm our hearts!

5 responses to “Mac OS Big Sur Freezing fix”
  1. Eugene Avatar

    i have reported to Apple support recently, if i can recalled, total 3 times.
    1st reported, they asked me to shutdown and reboot in safe mode then restart. Asked me to monitor if freezing still occurs. But it does not help to solve the freeze issue…the problem reoccurs.
    I called 2nd time and reported with same case number. Apple support aware of my problem and told me to do another steps, Reset the System Management Controller (SMC) could be another soultion to this freezing problem. I followed the advice and told to monitor.. but the freeze repeated after few hours…
    i called 3rd time with same case number, now guess what… they asked me to backup my data and restore the OS. Well i followed their advice and restore the OS. However, this does not solve the freezing problem. It repeating and repeating….

    This is totally bad for Apple to advice without giving the permanent solution.

  2. Martin Turner Avatar
    Martin Turner

    None of this helps. I found that kernel_task and PKD often run at high priority for long periods of time. I even cleaned out my 2013 Mac Pro via a posting that said temp sensors were causing excessive kernel_task. THIS IS A BIG SUR BUG! It did NOT do this with Catalina and earlier; my bet is all the extended security checking that is now (over) done.

  3. Tim Avatar

    “Reset the sound preferences and the Startup Disk” How does one reset these preferences? I know how to change them, but I’ve never heard of “resetting” them.

  4. Mitsu Avatar

    Your solutions above do not fix the problem. See for a full discussion. I HAVE found what appears to be a solution, and I hope you see this comment so you can update your answer above.

    Simply reinstall Big Sur without wiping your drive. Yes, it sounds counterintuitive – you just upgraded Big Sur, why install it again? But that’s what I ended up doing. After leaving it on for over 6 hours it hasn’t frozen yet.

  5. Mitsu Avatar

    Addendum to my comment: You can reinstall Big Sur but KEEP all your programs and files. THIS is the crucial step. If you upgrade in some cases Big Sur gets into this weird state where all Apple apps (messenger, Safari, calendar, etc.) start to freeze up after a short while after rebooting. But, without wiping your drive, reboot in recovery mode and reinstall Big Sur. This fixed it for me, finally.

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