Fix problems with the drive in disk utility on mac A usb drive showing the disk is write protected can prevent you from copying, deleting, or formatting files Make sure the usb drive's lock switch isn't set to lock or read only.
How to Format Read-only USB Drive Successfully? [5 Methods]
The usb should be the last one in the list
Now type select disk # (# being the number of your usb flash drive)
Type attributes disk to see the current read status of the drive. Follow the 5 disk read only fix solutions on this page and try to change a hard drive from read only on your own.