backuphard drivessdtime-machine
I want to also back up my external drive to another Time Machine drive, but when I want to stop Time Machine from excluding it, I can't, since it's not clickable:
I know the problem is, that it has to be in another format (currently ExFAT). But which formats are compatible and which are best?
You need to open the backup drive as a different backup disk.
This can be accomplished from the Time Machine menu icon, click on it then press alt and the menu will change from:
to:
I would also recommend reading these excellent pages on Time Machine backups.
Turn off Time Machine with the switch in System Preferences, then remove the Backups.backupdb from drive A.
Time Machine should recognise that the disk is no longer a Time Machine backup destination, but if it doesn't, delete .com.apple.timemachine.donotpresent from the root of the disk.
Best Answer
According to this article, the external drive has to be either an HFS+ drive or (since Big Sur) an APFS drive! I tested it with an external "APFS encrypted" drive and it worked. I was able to disable the exclusion in the settings and thereby back up the external drive to Time Machine!