To fix write-protection errors on a USB flash drive, disable the Write Protect mode by moving the mechanical switch on the drive to the unlocked position, and check whether there’s enough free space on the drive to accommodate the files you’re trying to copy. If this fails, disable write protection by modifying the WriteProtect value in Registry Editor, or format the drive altogether.
Plug in your USB drive, open Windows Explorer, right-click on the drive, and select Properties from the context menu. If there isn’t enough free space, access the drive, and remove unnecessary files. If you get the write-protection error while modifying a file on the drive, access the file's Properties dialog box, uncheck the Read-Only box, and click OK.
To disable write protection via registry, click Start, type “regedit” in the search field, and click on Regedit in the list of programs. Click Yes when the User Access Control prompt appears, double-click on the HKEY_LOCAL_MACHINE folder, double-click on SYSTEM, and then double-click on CurrentControlSet. Open the Control folder, click on StorageDevicePolicies, right-click on WriteProtect, select Modify, type “0” in the Value Data field, and click OK. If these steps fail, format the drive by right-clicking on it from Windows Explorer, selecting the Format option, choosing the desired File System and File Allocation Size settings, and clicking Start. Back up the files on the drive, and uncheck the Quick Format box before proceeding with this process.