How do I delete files from my Flash Drive

Plug the Flash Drive into your iMac and open Applications>Utilities>Disk Utility. There, select the flash drive in the left hand column by highlighting it and click "Erase" in the upper right hand tabs, then confirm Erase. That'll do it.

Hope this helps 🙂

I have the same problem. I went through disk utility and selected erase. Another window popped up with options that I can't understand. I chose Mac extended (including fonts and journaled).

When I then copied another file to USB disk, it was not functioning.

Any suggestions please?

Drag and drop them into the trash, then FINDER > SECURE EMPTY TRASH.