The disk is not writable. Insert a writable disk to continue. Write the following information on the disk, insert the disk, ...

The disk is not writable. Insert a writable disk to continue. Write the following information on the disk, insert the disk, and then click OK.  Media label: {0}  This information will be used by Windows Server Backup to identify this disk. Store it in a safe location so that you can use it for recovery.