Time Machine wants to be renamed
I'musing TM to backup both my iMac and my wife's MacBook Pro. Since installing Big Sur on the iMac (MacBook runs Catalina) The iMac won't backup, gives an error message that one of the discs needs to be renamed. How do I tell which is which, and how do I rename it?
iMac 21.5″, macOS 11.0