How to a remove Hard Drive from Time Machine Backup to Stop Backups to That Drive from a Mac

The context is 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:

  1. From the  Apple menu, choose ‘System Preferences’

  2. Access Time Machine system preference panel, then scroll down in the drive list to click on “Add or Remove Backup Disk”

  3. Choose the hard drive from the list that you want to remove from Time Machine backups, then click on “Remove Disk”

  4. Click on “Stop using this disk” to confirm that you want to remove the drive from Time Machine.