Late 2019 iMac by Apple running very slow and laggy after Big Sur update broken not working

I’m sharing an iMac Late 2014 (the oldest computer that is said to work with Big Sur)

It was very slow so we fully wiped the computer and installed a fresh copy of Big Sur, and it was still very slow, laggy etc.

We left the computer on doing nothing for 2 days and now it’s fully fast as it was before – there are 2 days of background update processes that the mac doesn’t tell you about…


If you have the issue:

late 2014 iMac by apple running very slow , not working, broken, frozen, update failed

Try leaving it on for 2 days to finish installing.