I just upgraded my MacBook Air to 11.1.
I used to run regular backups on a WD 1TB disk using Time Machine. But for a couple of days, the backup has not completed, issuing a "cannot find disk" error. It just managed to complete a backup two days ago after the upgrade to 11.1.
I have erased the disk through Disk Utility, but I encounter the following errors when trying to further format or mount it. The disk's name is disk2s2.
Mounting on Disk Utility
Could not mount “disk2s2”. (com.apple.DiskManagement.disenter error -119930868.)
diskutil eraseVolume ExFAT MyName disk2s2
The target disk is in use by APFS as a Physical Store; use diskutil apfs deleteContainer
sudo diskutil eraseDisk HFS+ backupMac /dev/disk2s2
A volume was specified instead of a whole disk: /dev/disk2s2
Specify a whole disk, or instead use diskutil eraseVolume to erase a volume on a specific partition
diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk1 250.8 GB disk0s2
/dev/disk1 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +250.8 GB disk1
Physical Store disk0s2
1: APFS Volume Macintoch HD - Data 142.2 GB disk1s1
2: APFS Volume Preboot 293.3 MB disk1s2
3: APFS Volume Recovery 613.6 MB disk1s3
4: APFS Volume VM 5.4 GB disk1s4
5: APFS Volume Macintoch HD 22.7 GB disk1s5
6: APFS Snapshot com.apple.os.update-... 22.7 GB disk1s5s1
/dev/disk2 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_APFS 999.8 GB disk2s2
sudo diskutil repairVolume /dev/disk2s2
Started file system repair on disk2s2
Error: -69564: Unable to find an APFS Container Reference
sudo diskutil verifyVolume /dev/disk2s2
Password:
Started file system verification on disk2s2
Error: -69564: Unable to find an APFS Container Reference
I feel out of ideas.
Best Answer
This solution eventually worked for me, I erased again the disk through Disk Utility, but giving it a different name. I also erased the disk in the Time Machine preferences, and then assigned the "new disk". It could then be found and a backup is currently on-going.