cgsecurity.org

Good afternoon,

A few days ago, I got the error message "You need to format before you can use it". Some minutes before that, the USB drive still worked (I was copying some folder to it).

I tried Recuva (-> "Unable to determine file system type") and PhotoRec ("Partition P unknown").

I quickformated the USB-drive, but still got 0 results on Recuva and PhotoRec.

Anything else I can do?

Run PhotoRec. In the Options menu, set the Expert mode. Start a recovery, choose a blocksize of 512 bytes, use the default options otherwise.
It may be able to recover some files this way.