It does sound as that may the case.
That is strange though because I have reslung both of my slugs many times in the past.
The last time I used then was with a pair of 2.5″ laptop drives fitted in cheap usb powered enclosures.
I am not using my slugs anymore now since I rely on the LSII’s, so I cant really comment much further.
I assume you have been using V5.5. I always found that the best version.
I think personally you would be better off reformatting that drive, and starting from scratch
Why not connect the drive to a PC and use a EXT3 file system driver to backup your data first ?
Or get yourself another drive they are really cheap now.
I have never tried unslinging to a flash drive so cant really comment. I didnt really like the idea of all the fiddling about
preventing unnecessary writes to the flash etc.
The slug also has a reset to factory defaults option in the menu too, I have had to use that on occasion.
Best of luck.