Accidental powerdown during backup to external hard drive leaving external hard drive inaccessible

I am a new user of Qubes; it’s been working great so far.
But yesterday I attached an external hard drive via USB to do a backup (like I normally do each week), and I accidentally let the computer (Purism Librem 14) power down. When I went to boot back up again and restart the backup, that’s when I realized that, while I can connect the device to a qube (and it shows as connected in qvm-block after attaching), when I try to read the drive in Nautilus, it just spins and my folders/files don’t appear.

I’m at a loss as to what to try at this point… any suggested instructions for next steps for me?


Additional information, if helpful. I connected the drive to an older Macbook Pro and got the following information from Terminal:

mbp:~ user$ diskutil verifyDisk /dev/disk2
Started partition map verification on disk2
Checking prerequisites
Checking the partition list
Checking the partition map size
Checking for an EFI system partition
Checking the EFI system partition’s size
Checking the EFI system partition’s file system
Checking the EFI system partition’s folder content
Problems were found with the partition map which might prevent booting
Error: -69854: A disk with a mount point is required