
Deleting a Hard Drive from Time Machine Backup to Stop Backups to That Drive from a Mac
Note that you do not need to have the drive connected to the Mac to remove it from Time Machine, this process is the same in all versions of OS X:- Pull down the Apple menu and choose ‘System Preferences’
- Go to the Time Machine system preference panel, then scroll down in the drive list to find “Add or Remove Backup Disk” and click that
- Select the hard drive, disk, or backup volume that you want to remove from Time Machine backups, then click on “Remove Disk”
- Confirm that you want to remove the drive from Time Machine and stop backing up to the disk in question
- Exit out of System Preferences when finished



Again, this does not delete any of the data from the Time Machine drive, it simply stops backing up to the drive that has been removed. This also does not turn off Time Machine.
If you want to, you can remove the actual Time Machine backup files from the drive in question yourself, or even format the drive to be Mac compatible and wipe it completely clean of any other data. There’s also nothing wrong with leaving the files there if you think you’ll need it again down the road or refer to them in the future.
Regardless, you’ll want to be sure you have some form of backup going to Time Machine or to another service, never let your Mac or iOS devices go without backups!
Source Url and Image: How to Remove a Disk from Time Machine on Mac