Shared Folder Vanished!

[pobotrol]

Hello,
I'm using an F5-221 TOS version 5.1.37-00031 (as advised by Terramaster Support)

I've spent the last week rebuilding a TRAID Storage Pool with 3 10TB HDDs. I've now got 18TB capacity Volume of which I've used 9TB in a Shared folder (imaginatively called "Shared").

I wanted to copy some more files onto the volume from an old HDD with a single volume which had been used on the NAS pre 5.1, it booted OK and I could access the files on the old volume, but in doing so it seems to have removed my "Shared" shared folder. This is even after rebooting the NAS without the old HDD in.

The folder has gone from Shared Folders and from the File Manager. However the Volume and the Storage Pool are still there saying the correct expected Capacity and Free Space. I can create a new Shared Folder, but no way to access the missing folder or my files

Has anyone got any ideas on how to get my files back?

[pobotrol]

Sorry, wrong screenshot, but you can see the lack of the shared folder, I guess!

Here's the correct screen of the Storage Pool.

[pobotrol]

Scrap this, it's come back after a third reboot! Weird!
Now to try a different strategy to retrieve the old files! The adventure continues!

[TMzethar]

Hope I didn't misunderstand you, are you installing TOS5 new HDD and old HDD at the same time on the same device? This will cause exception.
If a similar situation occurs again, you can collect a system log and send it to the technical support mailbox to help you analyze the problem.

[pobotrol]

Thanks, yes, the system really didn't like it, so I won't be doing that again!
Unfortunately my new Shared Folder seems to have gone for good now, despite the Storage Pool and Volume being maintained.
I've logged it with Support, who are looking into it.

In the meantime I'm looking for a method to retrieve the data on the old disks, hoped this would be simple as I'd set it up as a Single Disk.

I tried Paragon Linux File Systems for Windows but it errored whilst trying to mount the disk (seventeen quid wasted!!!)

I also tried mounting it in an Ubuntu VM, it could see the HDD and partition.

But when I tried to mount it I got an error... unknown filesystem type 'linux_raid_member'
The Google results for that were too scary and complex for me to understand!

Is there any known method for accessing data from disk partitions built in TOS, except from TOS?