Failed Installation of macOS Catalina I recently had to erase my 2018 Mac mini and I’m now trying to upgrade to macOS Catalina 10.15.6. However, after running the installer, I keep getting the error message “An error occurred while preparing the installation. Try running this application again.”
I’m not sure why this is. I’ve ran it 4 different times, restarted, deleted and re-installed the installer for Catalina, and nothing happens. Still getting the error message. Is there any way I can fix this and get it to work? Had the same issue while trying to re-install Catalina on another machine after resetting. Not sure what to do here.
There was a known issue with upgrading or installing the OS on Macs with a T2 chip to macOS 10.15.6. Apple have yet to acknowledge the problem but have rolled out (about 3 hours ago) a new update to the software catalog that is reported to fix the problem.
Give it another try after 0000 UTC Thursday Aug 6 as Apple has replaced a wrong installer for most T2 Macs.