Encrypted USB disk not shown in Finder after unlocking I have an encrypted USB stick. I put it in the USB slot on my MacBook Air, then I input the passphrase but nothing happens: the USB doesn't show up on Finder and doesn't mount.

I can see the USB stick in Disk Utility and when I run First Aid on it I receive an error.

$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Untitled                120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650 MB     disk0s2
/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS HDD                    +120.1 GB   disk1
                                 Logical Volume on disk0s2
                                 5C2DFE14-9CA0-471D-A048-74B0DD09A04C
                                 Unlocked Encrypted
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *8.1 GB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:          Apple_CoreStorage Rotschild               7.7 GB     disk2s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk2s3
/dev/disk3 (external, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                 Apple_HFSX Rotschild              +7.3 GB     disk3
                                 Logical Volume on disk2s2
                                 CEC0286A-19BD-4390-9A16-E05AED538CA2
                                 Unlocked Encrypted
$ diskutil mount Rotschild
disk3 is a CoreStorage Logical Volume which failed to mount
$ diskutil mount disk3
disk3 is a CoreStorage Logical Volume which failed to mount
$ diskutil mount disk2s2
disk2s2 is a FileVault or Fusion Drive physical volume; use "diskutil coreStorage list" to find its logical volume, which you can then unlock (if necessary) and mount
$ diskutil coreStorage list
CoreStorage logical volume groups (2 found)
I just had to solve this issue this morning. I though the USB was ruined but it turns out it was something to do with btrees caused by a write error. Tech Tools Pro identified it and fixed the issue. I also have Disk Warrior 5 and probably would have worked as well.