Seagate HDD.
Since 2020? Last recreated the TM backup March 26, 2024.
5TB capacity.
Used 2.6TB.
First aid on the drive runs fine:
Running First Aid on “Seagate BUP BK Media” (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
Checking all HFS data partition loader spaces
Checking booter partitions
Checking Core Storage Physical Volume partitions
The partition map appears to be OK
Operation successful.
First aid on the APFS Container fails because the disk is mounted.
First aid on the APFS Volume fails because the disk is mounted.