open a CMD window
run CMD
in DOS run "diskmgmt.msc"
in DOS run "diskpart.exe"
New window opens.
In new window prompt is "DISKPART"
In DISKPART run "rescan"
In DISKPART run "list disk"
My bad USB Stick is listed "Disk 1"
In DISKPART run "select 1"
In DISKPART RUN "CLEAN" should get msg...