It sounds like a problem with the cart if you've tried it on different computers. That's the best I can offer.

So you said you were able to backup your stuff from an EMS64 cart using a transferrer cable? Hm. I never would have thought of that.

I had the luck of being able to lend a transferrer, that still works. So it's something.
But other than that, still no results

i have had this problem as well, and have tried the same things to troubleshoot.. no luck for me either

So yeah, this sucks.

I was doing some backups and LSDJ updates on a cart, and when writing a new lsdj version, GB_USB crashed, computer froze, bleh.

So, I had to yank out the cartridge. luckily the save file and the lsdj version still work fine, but now everytime i want to connect the cart to a computer, it says "unknown device"
It won't recognize it as an EMS interlink cable device anymore.

I tried:
different cables
different computers
reinstall of the drivers.

does nothing really.
I'm just glad i just patched it with littleFM so i can still transfer my songs to another card if needed, but if someone knows a solution to this problem, it would be very welcome.