I'm dealing with several issues on an encrypted backup disk on my Mac, and I'm seeking advice. The disk has two partitions, and I've encountered different errors for each section and the container. Here are the specifics:

  1. Backup Partition Issue:

    • Error when attempting to unlock (password is definitely correct):
      "SunBackupSSD" can't be unlocked. 
      A problem was detected with the disk that prevents it from being unlocked.
    • Disk Utility First Aid on the backup partition reports:
      File system check exit code is 1.
      Restoring the original state found as unmounted.
      File system verify or repair failed. : (-69845)
  2. Full Disk Error:

    • Running First Aid on the entire disk ("SanDisk Extreme 55AE Media") yields:
      Checking prerequisites
      Problems found with the partition map, which might prevent booting
      Internal lookup error: (-69808)
      Some information was unavailable during an internal lookup
  3. Container Unlocking Issue:

    • Trying to unlock the container where the backup is stored results in:
      Running First Aid on "Container disk5"
      The verify and repair cannot be performed because one or more volumes are locked. : (-69502)
      Operation failed...

I'm certain the password for the encrypted backup is correct. I'm looking for guidance on these error codes (-69845, -69808, and -69502) and any steps I can take to safely access and recover the data. Thanks in advance for your help!

here is structure of disk

or diskutil list output:

/dev/disk4 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk4
   1:                        EFI EFI                     209.7 MB   disk4s1
   2:                 Apple_APFS Container disk5         1.0 TB     disk4s2
                    (free space)                         134.7 MB   -
   3:       Microsoft Basic Data                         999.9 GB   disk4s3

/dev/disk5 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.0 TB     disk5
                                 Physical Store disk4s2
   1:                APFS Volume SunBackupSSD            928.4 GB   disk5s2

Filanlly, I tried verify disk with CLI diskutil verifyVolume disk5s2

Which gets

Started file system verification on disk5s2 (SunBackupSSD)
Verifying file system
Volume is already unmounted
Performing fsck_apfs -n -x /dev/rdisk5s2
error: failed to read container superblock
Container superblock is invalid
The volume /dev/rdisk5s2 with UUID 00000000-0000-0000-0000-000000000000 could not be verified completely
File system check exit code is 8
Restoring the original state found as unmounted
Error: -69845: File system verify or repair failed
Underlying error: 8
  • Apple recommends you run First Aid in 'reverse order' - [all] volumes, containers, disks, upwards through the list. support.apple.com/102611
    – Tetsujin
    Commented Dec 19, 2023 at 10:23


You must log in to answer this question.

Browse other questions tagged .