We have erased everything on our old iMac mid 2012. We wanted to donate it to charity but after spending almost 1 hour with Apple on the phone, it was determined that the OS could not be reinstalled. Can someone tell me if this is even possible?
While donating seems like a noble endeavor, it can actually be a curse for the end recipient.
To top that off, the directions at > What to do before you sell, give away, trade in, or recycle your Mac - Apple Support are geared towards later Mac's and macOS versions.
Sadly, the best course for a 12 year or older iMac is recycling.
There were no Mid 2012 Macs – so I assume that you are talking about a Mid 2011, Late 2011, or Late 2012 model.
Depending on the age of the Mac, it might theoretically support Internet Recovery. I don't know how well Internet Recovery would actually work these days, and even if you got the original version of the operating system installed, that would be old enough that it wouldn't be able to directly access the update for the most recent OS the machine could run (High Sierra for the 2011 models, Catalina for the 2012 ones).
There are ways around that, and if this is a 2012 Mac that can run Catalina, Catalina is new enough to run current versions of the Firefox Web browser, the LibreOffice office suite, and the Affinity V2 applications (Photo, Designer, Publisher). Someone who was aware of the limitations of a 2012 iMac could still get some good use out of it.
However, even Catalina is too outdated to run current applications from the likes of Microsoft and Adobe. If what a charity wants is a computer to run current applications, you may find that they do not want such an old machine.
installing Mac OS into an imac Mid 2012
