Chosen Solution
Bought a 2018 MacBook Pro 15” from a 3rd party recently, which has Mojave installed and running fine, however, try to upgrade it to Big Sur or Catalina, it always return the following message (a small window pops out, which is about 9 or 10 minutes left toward finishing): “An error occurred installing MacOS. You may try again to complete the installation” Firstly I thought it might be something wrong with Apple server, but have this message shows up every time doing software upgrade, so, I think it must be something else. Does anyone have any thoughts what could be wrong with this laptop, or some hidden settings which prevent the OS to be upgraded? Thanks,
As this is a used system are you able to contact the original owner to have them remove the system from their iCloud account? Sadly, your system is linked as it won’t allow you to alter the drive until it’s either logged into iCloud or the system is removed from the users equipment listing.
