If the StorageDevicePolicies does not exist, create it manually by right-clicking on the control key and selecting New -> Key. In the right window, double-click on WriteProtect, and set the value to 0. If WriteProtect does not exist, then right-click on the new StorageDevicePolicies...
If WriteProtect does not exist, then right-click on the new StorageDevicePolicies key and select New –> Dword, specify the name as WriteProtect, double click the WriteProtect and set the value to 0.If it is an external hard disk, disconnect the hard disk and reconnect it. If ...