I have an external 4TB SSD, formatted HFS (MacOS Extended, Journaled, encrypted). It has one volume, called "Daten".

All of a sudden (after installing 10.14.6 Supplemental Update) the volume no longer mounts.

In disk utility the volume is greyed out and has a strange new name:

"Daten[many blanks]3111002011"

Selecting the Drive and running First Aid shows no error.
When selecting the Volume, First Aid is greyed out.
[edit: First Aid is possible via the File menue. It fails with the error: "Invalid request. Operation failed…"]

This is the output of diskutil coreStorage list and an attempt to mount and verifyVolume:

$ diskutil coreStorage list
CoreStorage logical volume groups (1 found)
+-- Logical Volume Group F8B554D1-4504-4CB8-9E2C-867BE08442DC
    Name:         Daten
    Status:       Online
    Size:         4000451620864 B (4.0 TB)
    Free Space:   0 B (0 B)
    +-< Physical Volume DDD64DF2-295D-440A-BE08-4E36316DA943
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk2s2
    |   Status:   Online
    |   Size:     4000451620864 B (4.0 TB)
    +-> Logical Volume Family A6CDDA9C-50BC-452A-961C-188A6D44CF05
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Complete
        High Level Queries:      Fully Secure
        |                        Passphrase Required
        |                        Accepts New Users
        |                        Has Visible Users
        |                        Has Volume Key
        +-> Logical Volume 8FDE568D-88A5-4093-BA2A-320646BC10AC
            Disk:                  disk3
            Status:                Online
            Size (Total):          4000099295232 B (4.0 TB)
            Revertible:            No
            LV Name:               Daten                                                                                                                                               3111002011
            Content Hint:          Apple_HFS
$ diskutil mount readOnly disk3 
Volume on (null) failed to mount
If the volume is damaged, try the "readOnly" option
$ diskutil verifyVolume disk3
Unable to obtain whole-disk size

What happened here? Is there a way to repair the volume?

I can just reformat and restore from backup, but maybe somebody knows a better solution and is able to share his/her knowledge on this matter.

  • If you go to disk utility, select the grayed disk, then go to File menu, there will be a option for you to unlock it. Did you try it? What happens? – Prado Aug 10 at 23:11
  • There is no unlock option but a mount option. Tried it, nothing happens. – Martin Ackerl Aug 11 at 7:56
  • any error messages? Just doesn't mount? Option is still active if you try a second time? I would try to keep Console App opened, an try to mount it, and catch any messages from the procedure on console.app – Prado Aug 13 at 14:53
  • Hi Prado, thanks for your hints. I could not wait any longer and just formatted the whole disk. Took a day to restore from backup but now it's working again. – Martin Ackerl Aug 13 at 19:00

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