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MacOS Big Sur slow performance after upgrade

Help with macOS Big Sur performance after a macOS software update or upgrade.

How to troubleshoot Apple MacOS Big Sur slow performance after upgrading to Apple MacOS Big Sur.

Our Apple Mac computer technicians explain why Apple MacOS Big Sur might be slow after upgrading a Apple Mac computer to MacOS Big Sur. Read our free guide on how to fix the problem with Apple MacOS Big Sur slow performance on a Apple Mac computer.

If you have just upgraded to Apple MacOS Big Sur and the performance of the Apple Mac computer has become slow or very slow, in most cases the Apple Mac computer needs more time to complete the upgrade. Many tasks will run in the background.

What happens after you have upgraded to MacOS Big Sur!

The following background tasks will often run or start after upgrading to Apple MacOS Big Sur operating system software.

  • Spotlight – The Spotlight Index is updated in the background.
  • Mac Mail – The Apple Mac Mail application is updating the Apple Mail database.
  • iCloud – The Apple iCloud Drive is setting up and optimising the iCloud Desktop and Documents folder.
  • Photos – The Apple Photos application is uploading original files to the Apple iCloud Photos Library.
  • Photos – The Apple Photos application is optimising the Apple iCloud Photos Library file.
  • MacOS software updates – The app store is downloading Apple MacOS updates and software updates.
  • Apps – Applications that are opened for the first time after a upgrade to MacOS Big Sur need to optimise.
  • Incompatible software – A application that is not fully compatible with Apple MacOS Big Sur is causing the computer to become slow.
  • Time Machine Backup – The performance of a SATA disk can be slow whilst the Time Machine backup process runs.

All of the above tasks need to complete after you have upgraded to MacOS Big Sur. Simply allow more time for MacOS Big Sur to perform and complete the tasks. Most of the tasks will complete after a day or two if you have a high amount of data.

Time needed: 59 minutes.

How to troubleshoot Apple MacOS Big Sur slow performance after upgrading to MacOS Big Sur.

  1. Optimise the Storage volume.

    1. Open the Apple Menu items and select About this Computer Menu.
    Select the Storage tab.
    Click Manage.
    Follow the Recommendations.

  2. Optimise the Memory.

    Open the Users and Groups control panel from the System Preferences menu.
    Click on the Login Items Panel.
    Remove all of the items in the startup items list.
    Quit all of the applications that are open in the Dock apart from the Finder.
    Select the Apple logo and choose Restart…
    Untick the “Re open Windows when logging back in”
    Restart the Apple Mac computer.

  3. Uninstall applications.

    Remove any applications that are no longer used.
    Ask a Apple Mac computer technician for advice and assistance if required.

  4. Manage the Startup Items.

    Optimise the Apple Mac computer by stopping any applications from opening when the Apple Mac computer starts up.
    Examples • Spotify • Microsoft Office for Mac • Adobe software. Third party utilities.

  5. Perform a Apple Mac security check.

    Use a Apple Mac computer software tool to perform a Apple Mac computer virus and Apple Mac security check.
    Consult with a Apple technician on the best tool to use.

  6. Uninstall Adobe Flash and Oracle Java.

    Visit the Adobe Flash Player website and download the Adobe Flash Player removal tool from.
    Visit the java.com website and use the java removal tool.

  7. Remove any 32-bit applications.

    Ask the software vendor for software tools to remove the 32-bit code from your Apple Mac computer running MacOS Big Sur.

  8. USB and external devices.

    Temporary remove any external USB storage volumes and memory sticks from the computer to troubleshoot a slow USB device.

  9. Update to the latest version of MacOS Big Sur.

    Use the Apple Software Update icon to allow the Apple MacOS Big Sur operating system download and install any MacOS updates.

What is the best way to speed up MacOS Big Sur?

The best way to speed up MacOS Big Sur is to upgrade from SATA to SSD on a Apple iMac or MacBook Pro computer that has an older SATA storage volume fitted. A SSD is 66% to 70% faster than a SATA storage volume.

Further Reading on Apple Mac computer maintenance.

Apple MacOS Big Sur performance FAQ questions and answers!

What is the best way to improve the performance of MacOS Big Sur?

Use SSD solid state flash storage technology.
Upgrade the memory ram from 8Gb to 16Gb can improve the performance on supported Apple Mac hardware.

Does the Apple MacOS Big Sur operating system need regular computer maintenance?

No. The built in Apple MacOS Big Sur storage maintenance tools keep the Apple MacOS Big Sur running.
Its a good idea to leave the Apple Mac computer switched on for 12 to 24 hours so that the built in MacOS maintenance scripts can run.

Which version of Microsoft Office for Mac is optimised for Apple MacOS Big Sur?

Microsoft Office for Mac 2019 with all of the updates installed is optimised for Apple MacOS Big Sur.

How can I get help with a slow Apple Mac computer?

Keith Thomas provides an Apple Mac computer maintenance service for slow Mac computers in the UK.
Complete the online website contact form for assistance.

How to get help with a slow Apple Mac computer in the UK?

  • Complete the online website contact form. (open 24 Hours) with 10:30 am to 21:00 pm response times for completed forms sent to us.
  • Our online website contact form only takes a few minutes to complete on your • computer • phone • tablet device.
  • We respond by email: we are open daily from 09:30 am to 20:30 pm • 7 days a week service! including weekends and Sundays!
  • For Apple Product Repairs for Hardware and Apple Service, use the Apple Product Repairs button!
  • Call or Text 07800 940756 lines open 10:30 – 13:00, 14:00 – 17:00, 18:45 – 20:30