No "Select Backup Disk" Button in the Time Machine Preference Pane
I want to use a new backup disk with an iMac running Sierra. Several previous backup disks are listed. However the button to select a new disk, and/or to remove the previous ones, is nowhere to be seen...! The only clickable items in the preference pane are:
- Select/deselect automatic backup
- An error message for one of the previous disks (with Accept as unique button)
- Select/deselect show Time Machine in the menu bar
- The Options... button which doesn't allow selecting a new disk
How can I select a new backup disk?
iMac 27″, macOS 10.12