iMac can't boot because of an unrecoverable error
I'm having trouble trying to fix my parent's iMac - it's hanging up while booting, always showing the same error message that I can't get past.
I keep getting this error message:
I've tried opening with extensions switched off; booting into diagnostics mode & recovery mode; none of which have worked; I've tried re-installing the Mac osx (Catalina), using recover mode, but the computer won't re-install the Mac OS (it hangs up at the end of the download)
I'd happily re-format the drive, but I need to back up the data from it first (I have a MacBook Pro, so I'm going to try backing up all the relevant data using that, and then re-format the HDD of the iMac).
I'd love to hear any suggestions!
thanks!
Andrew
iMac Line (2012 and Later)