To no avail I've reformatted a Samsung QVO 8TB SSD as APFS with GPT so that I can use that external for iPhone backups with a symlink. Unfortunately, every time I format the SSD as APFS it never mounts on my mid-2023 MacBook Air. For some reason I can mount the SSD on a much older MacBook Pro from a decade again.
I'm really trying to figure out what the issue is, and why my system won't let me reformat the SSD to APFS GPT and mount, yet it allows me to use the ExFAT scheme and MBR format. After reformatting the SSD to APFS, I'm shown output that reads "Could not mount disk5s1 after erase". The SSD also doesn't appear in Finder, thought it is visible using Terminal or Disk Utility.
If I need to provide any additional context I will, any help would be appreciated.
Operating system: Tahoe Version 26.1
diskutil list output before reformatting:
% diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: Apple_APFS_ISC Container disk1 524.3 MB disk0s1
2: Apple_APFS Container disk3 245.1 GB disk0s2
3: Apple_APFS_Recovery Container disk2 5.4 GB disk0s3
/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +245.1 GB disk3
Physical Store disk0s2
1: APFS Volume Macintosh HD 12.2 GB disk3s1
2: APFS Snapshot com.apple.os.update-... 12.2 GB disk3s1s1
3: APFS Volume Preboot 8.2 GB disk3s2
4: APFS Volume Recovery 1.2 GB disk3s3
5: APFS Volume Data 212.2 GB disk3s5
6: APFS Volume VM 3.2 GB disk3s6
/dev/disk4 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *8.0 TB disk4
1: Windows_NTFS Mark VIII 8.0 TB disk4s1
APFS formatting output:
% diskutil eraseDisk APFS "Mark VIII" GPT /dev/disk4
Started erase on disk4
Unmounting disk
Creating the partition map
Waiting for partitions to activate
Formatting disk4s2 as APFS with name Mark VIII
Mounting disk
Could not mount disk5s1 after erase
Finished erase on disk4
ExFAT scheme with GPT formatting output:
% diskutil eraseDisk ExFAT "Mark VIII" GPT /dev/disk4
Started erase on disk4
Unmounting disk
Creating the partition map
Waiting for partitions to activate
Formatting disk4s2 as ExFAT with name Mark VIII
Volume name : Mark VIII
Partition offset : 77056 sectors (315621376 bytes)
Volume size : 1953429504 sectors (8001247248384 bytes)
Bytes per sector : 4096
Bytes per cluster: 262144
FAT offset : 4096 sectors (16777216 bytes)
# FAT sectors : 32768
Number of FATs : 1
Cluster offset : 36864 sectors (150994944 bytes)
# Clusters : 30521760
Volume Serial # : 6916770f
Bitmap start : 2
Bitmap file size : 3815220
Upcase start : 17
Upcase file size : 5836
Root start : 18
Mounting disk
Finished erase on disk4
diskutil list output after reformatting:
% diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: Apple_APFS_ISC Container disk1 524.3 MB disk0s1
2: Apple_APFS Container disk3 245.1 GB disk0s2
3: Apple_APFS_Recovery Container disk2 5.4 GB disk0s3
/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +245.1 GB disk3
Physical Store disk0s2
1: APFS Volume Macintosh HD 12.2 GB disk3s1
2: APFS Snapshot com.apple.os.update-... 12.2 GB disk3s1s1
3: APFS Volume Preboot 8.2 GB disk3s2
4: APFS Volume Recovery 1.2 GB disk3s3
5: APFS Volume Data 212.3 GB disk3s5
6: APFS Volume VM 4.3 GB disk3s6
/dev/disk4 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *8.0 TB disk4
1: EFI EFI 314.6 MB disk4s1
2: Microsoft Basic Data Mark VIII 8.0 TB disk4s2
diskutil listfrom a Terminal session (cut & paste, no screenshots), from when it reportedly doesn't work with APFS, and when it does work with ExFAT. There's quite a few variables at work here and there needs to be clarity on what combinations have been tested.eraseDiskis not creating the APFS container structure. The UI will perform more steps to create a default container and volume.diskutil listoutput after the failed cli APFS format attempt? That would make it clearer what steps were performed up to the point of the failed mount, and thus what steps were missing.