I use an iMac as an external monitor for my MacBook pro (OS X 11.6), over a thunderbolt cable. I usually have a USB 3 hard drive attached to my MacBook pro as a Time Machine backup. Last week I thought I would try attaching my USB drive to my iMac, and mounting it as a shared network drive over the thunderbolt network bridge. Of course, Time Machine then created a
.sparsebundle disk image to perform the backup over the network. I decided I didn't want to start a full backup from scratch, and so moved the USB drive back to a direct connection.
However, now Time Machine only wants to back up to the
.sparsebundle image, even thought the drive is connected locally and has a full set of backups at the root of the drive (in
Backups.backupd). I tried using
tmutil setdestination and
tmutil associateddisk -a to force the association, with no success. I even renamed the
.sparsebundle, and every time I start a backup the
.sparsebundle is renamed back to the old name.
How can I stop Time Machine from treating the USB-attached hard drive as a network share for backups?