DesertDweller

OK then. Problem solved after 2 days and a 32 page AI chat.
Short version: Turns out (assuming that the AI engine is correct) there is a known bug in Linux/Unraid:
MFT metadata mismatch created by the NTFS-3G driver in Unassigned Devices (UD).
Although I had previously (and successfully) used 2TB NTFS drives connected to Unraid via USB/Unassigned devices, the same actions now creates this fatal error.


AI indicated that a reason might be because of a W11 update between "then" (maybe 6 months ago) and now..

So. Short version solutions:
Format your transfer drive under ExFAT (not NTFS) under W11, then attach to Unraid via Unassigned Devices. I used a 2TB drive and connected via the Unraid USB. I asked, and the AI engine confirmed that this should also work if connecting a HD directly to the SATA cables in the Unraid Server. In my 2TB/USB test, I was able to successfully copy files to the transfer drive, then unmount from Unraid, then connect to a W11 drive via USB, then copy files to NTFS drives.
If you already have several TB of data on NTFS drives that cannot be copied (like me), then there is a better solution. DL and install "TeraCopy" to your W11 machine, connect the formerly "Unassigned Device" drive via either USB or SATA, then copy the files to your NTFS formatted devices. It works! I also tested the "copied" file by copying it to another NTFS drive via File Explorer. It also works. The AI engine recommended TeraCopy, after trying several other solutions to identify the problem. It seems TeraCopy does not read the same file errors that Unraid created, and that causes File Explorer to choke.
TeraCopy works because it does not read the fil the same way as File Explore. I have used it occasionally in the past; but this program now saves me tend of hours of additional file transfers. Just purchased their Pro version for $29.95. best $ ever spent. And no, I have no financial interest in the company.
If anyone is interested, I made a link to the chat, as well as a copy of same in PDF. Mods - please advise if it is ok - or verboten - to post either.
Never having used AI for almost anything - let alone trying to figure out arcane file structure errors in transferring files between different operating systems - I found the interchange... fascinating.🤨
Not a far-removed interaction from Spock asking the computer to plot a course through the asteroid belt... 😃