If the registry key StorageDevicePolicies does not exist, you will need to create it manually.
c. Highlight StorageDevicePolicies, and then create a New DWORD (32-bit) Value named as WriteProtect.
d. Double click the key WriteProtect in the right window and set the value to 0 in the Value
Data Box and press OK button
e. Restart your computer and try copying files into your USB drives.