I have a 4TB Portable SSD, which is a Lexar M.2 in a Portable Enclosure.
And it works just Fine.
However I just Plugged it in to My Nas ( TS264) to do a Backup, and that’s when I found all this Junk had been put on it.
I have just introduced a new backup drive into my backup collection.
So I started out with a freshly formated drive ( Formated to NTFS ) from a windows PC.
And to Test it I Copied one of my Movies onto it.
I placed the Movie into a Folder named ( Movies ) and the Movie itself in a Folder Named ( 2 Guns ).
Now to Test this I Plugged the portable SSD into my smart TV and Watched this Movie ( 2 Guns ) .
That all worked out just fine.
Next I wanted to do a Full Backup from My NAS to the Portable SSD.
The amount of information in a Full Backup is Quite Big.
The Movie Folder contains about 2000 Movies, about 2.5TB, then there is about a dozen other folders.
All up about 3.5TB.
So I came back when it had finished , about 2 hrs later and all appears to be OK.
However when I plugged it into my Main Computer to have a Close look at my folders, I noticed Every Movie Folder had Some Folder or File, Named .@_thumb.
So I had to use some special software to Find them all and Delete them , about 2500.
These Files/Folders did not affect the Movies, just Used up Space.
The thing that Annoyed me is that a File Backup Feature Provided by Qnap could be Allowed to do that type of File Copy.
In File Station I just went and Highlited all My Folders then Clicked on Copy to ( to my portable SSD ).
I left all settings at their Default, that’s when I ended up with all this Junk.
QNAP generates thumbnails for all of your movie and image files so that you can see pretty icons when browsing in the NAS. You can select not to create thumbnails. But that’s what those are. They aren’t junk. Just ignore them.