Rescue Everything | Save My Gig

Step 1

Rescue everything first

Before touching anything else: get a full copy of the drive.

Create a folder on your computer: USB-RESCUE.
Copy everything readable from the USB into it, the whole drive, not just music.
Let it run; a slow copy is fine, an interrupted one is not.

Did everything copy successfully?

You follow these steps at your own risk. Full disclaimer.