Hello,
Upon Checking the Screenshot, we can see that SEP is running as Managed SEP.
Are you facing this issue, evern when you uninstall SEP from the machine?
This is not a Symantec Issue.
Try Contacting the Manufacturer of the USB Pen Drive
However, Try
Right Clicking My Computer and Choose Manage
Then at Computer Management choose Disk Management
At Disk2 Right Click at your "Protect Removable Disk" ex: "Removable Disk (F:)"
and Choose "Change Drive Letter and Paths for ....."
Simple Click "REMOVE", then Click "ADD", simple ....
Try to Format Yours then Try to Copy Another files