I have just inherited a late 2015 27” retina iMac. This was wiped for me, but left to me to reinstall the OS. I found an excellent thread on here which helped me get past an issue during reinstall of El Capitan by resetting the date. However, I am now unable to upgrade to any later versions of OSX. I have tried Catalina, Mojave and Monterey but all just get stuck in a processing loop.
Any suggestions on whether I need to ‘trick’ the OS, as I had to with the date for the El Capitan reinstall?
Any advice appreciated.