Time machine Macintosh and Macintosh HD - Data
I've read the posts and still cannot figure this out. I've been using TM with an external drive for many months without any issue. Today when I reinstalled Big Sur, I now have two drives, "Macintosh and Macintosh HD - Data". And when I want to set TM prefs to my external drive it's not available (only with an option to remove), but the drive appears a second time in the list under "available", which I select, and I still get the error message "two of the disks have the same name...." No matter what I remove or select to use I cannot get TM to work. My biggest concern is the potential to lose my last six months of TM backups. Thanks for your responses.
Mac mini, macOS 10.15