After coming back from holidays I discovered that the TM hard disk I connect to my Mac has stopped mounting.
The HD was encrypted with FileVault.
I tried with Disk Utility to mount it but it does not work.
diskutil mount /dev/disk3 hangs forever (1 hour then i stopped it)
diskutil repairvolume /dev/disk3
at some point it stops and gives these messages:
Load and verify Freespace Summary
Load and verify Block Accounting
Blocks on device E83429AA-8F51-4BB2-88CB-370A70F8003B are not accounted for by CoreStorage
Unable to bootstrap transaction group 30442: inconsistent crosscheck
No valid commit checkpoint found
The volume 17690DAF-921C-41DF-B225-3EAF5DF79F11 was found corrupt and needs to be repaired
Storage system check exit code is 1
Error: -69716: Storage system verify or repair failed
Underlying error: 1
What can I do to fix this?