there's a quick way to fix a usb write-protected error.. just make sure to copy all important files as you need to format the disk..
i don't know if it works on damaged or any other errors on usb coz my flash drive kingston datatraveler 100 g3 16gb has only write protect on it.. im using win 8.1 and I have already tried regedit, diskpart, safe mode format, and several usb tool but to no avail.. wasting several hours looking for a fix on a few months old flash drive..
download phison format and restore tool in my case i've used v3.13 I didn't try newer or other versions as my flash disk has been fixed using this one....
insert your usb flash drive.. run the app and click restore and select fat as I did but I dont know if selecting ntfs would also fix the problem..
DON'T REMOVE YOUR FLASH DRIVE EVEN IF IT TELLS YOU TO..
let the program finish and it would tell you to re-insert your flash drive after its completed.. don't follow it and just close the program, do not remove flash drive!!!
instead windows would tell that your flash drive needs formatting so format your drive and don't check quick format then start.. it will format your flash drive for about 5 or 10 minutes I didn't record the time and just browse on internet as the progress bar is very slow LOL.. after formatting your flash drive it will work normally now without the hassle of the write-protected error...