External Hard Disk Read Only Problem

This is driving me bananas!

I have a Lacie D2 Thunderbolt 2 that works fine with my 2012 iMac (Fusion) running Mojave but will only connect read only on my mid 2014 Retina 15" MBP running Mojave.

I thought it was a permissions problem so I erased the HDD from scratch to JHFS+. If I do this then the drive will not mount.

This is where it gets odd. After I have erased the disk (in terminal diskutil) then it will not mount on my MBP but if I plug it into my iMac then it mounts fine as a writeable drive. If I create a test file on my iMac, eject, then plug into my MBP then it will mount on the MBP but only as a readonly volume.

I have tried fsck_hfs, repairVolume, disableOwnership, eraseDisk, eraseVolume, repairDisk, resetUserPermissions

They all either work but don't fix or give me an error. Here are some examples from the MBP:

$ diskutil resetUserPermissions LACIE `id -u`

Ready to reset user permissions on disk2s2 LACIE

Started verify/repair permissions on disk2s2 LACIE

Error: -69838: Operation not supported for the macOS version on the targeted disk

$ diskutil eraseDisk JHFS+ LACIE disk2

Started erase on disk2

Unmounting disk

Creating the partition map

Waiting for partitions to activate

Formatting disk2s2 as Mac OS Extended (Journaled) with name LACIE

Initialized /dev/rdisk2s2 as a 3 TB case-insensitive HFS Plus volume with a 229376k journal

Mounting disk

Could not mount disk2s2 after erase

Finished erase on disk2

$ diskutil mount LACIE

Volume on disk2s2 failed to mount

If the volume is damaged, try the "readOnly" option

$ diskutil verifyDisk disk2

Started partition map verification on disk2

Checking prerequisites

Checking the partition list

Checking the partition map size

Checking for an EFI system partition

Checking the EFI system partition's size

Checking the EFI system partition's file system

Checking the EFI system partition's folder content

Checking all HFS data partition loader spaces

Checking booter partitions

Checking Core Storage Physical Volume partitions

The partition map appears to be OK

Finished partition map verification on disk2

$ diskutil repairDisk disk2

Repairing the partition map might erase disk2s1, proceed? (y/N) y

Started partition map repair on disk2

Checking prerequisites

Checking the partition list

Adjusting partition map to fit whole disk as required

Checking for an EFI system partition

Checking the EFI system partition's size

Checking the EFI system partition's file system

Checking the EFI system partition's folder content

Checking all HFS data partition loader spaces

Checking booter partitions

Reviewing boot support loaders

Checking Core Storage Physical Volume partitions

The partition map appears to be OK

Finished partition map repair on disk2

$ diskutil mount LACIE

Volume on disk2s2 failed to mount

If the volume is damaged, try the "readOnly" option

$ diskutil info LACIE

Device Identifier: disk2s2

Device Node: /dev/disk2s2

Whole: No

Part of Whole: disk2

Volume Name: LACIE

Mounted: No

Partition Type: Apple_HFS

File System Personality: Journaled HFS+

Type (Bundle): hfs

Name (User Visible): Mac OS Extended (Journaled)

Journal: Unknown (not mounted)

Owners: Disabled

OS Can Be Installed: No

Media Type: Generic

Protocol: SATA

SMART Status: Verified

Volume UUID: 0C6E44A2-054E-3B88-AE38-AFF5F0195AE4

Disk / Partition UUID: 40B10109-1FE0-4F22-9EA9-540A1973F875

Partition Offset: 209735680 Bytes (409640 512-Byte-Device-Blocks)

Disk Size: 3.0 TB (3000249008128 Bytes) (exactly 5859861344 512-Byte-Units)

Device Block Size: 512 Bytes

Volume Total Space: 0 B (0 Bytes) (exactly 0 512-Byte-Units)

Volume Free Space: 0 B (0 Bytes) (exactly 0 512-Byte-Units)

Read-Only Media: No

Read-Only Volume: Not applicable (not mounted)

Device Location: External

Removable Media: Fixed

Solid State: No

Hardware AES Support: No

If I then plug the drive into my iMac then it mounts the drive fine automatically and is read/write enabled.

Any ideas?!