If you are unable to resolve the USB Write Protection issue using following Registry Method How To Remove Write Protection on a USB using Registry .Please try removing Write Protection on USB using Diskpart method.
When enabled, write protection is a setting that blocks any sort of modification or deletion of a file on a disc.
If you are experiencing an issue when attempting to copy or delete files on a USB flash drive, there is a very simple solution that will allow you to remove this setting, giving you the capability to modify, copy, or delete any files from your USB drive.
To remove the write protection , simply Open your Start menu, and click on Run. Type in diskpart and press Enter. This will open the Diskpart Utiliy in the Command Prompt.
Now, at the prompt, type the following and press Enter after each command:
diskpart list disk select disk x (where x is the number of your USB flash drive) attributes disk attributes disk clear readonly attributes disk exit