When you select a backup media device in Backup (Ntbackup.exe), you cannot select a CD-R (compact disc recordable), CD-RW (compact disc rewritable), or DVD-R (digital video disc recordable) device.
This issue occurs because Removable Storage Management does not recognize CD-R, CD-RW, or DVD-R devices as backup pool media, even though you can add these media types in Removable Storage Management. Ntbackup.exe therefore does not support backup to these devices.
To resolve this issue, perform the backup to some other media type, for example, to a tape or to a hard disk.
This behavior is by design.
Removable Storage Management regards CD-R, CD-RW, or DVD-R as just a file system-capable media type. However, the Windows file system does not support formatting CD-R, CD-RW, or DVD-R media. Removable Storage Management cannot write an RSM free label because the disc appears to be write-protected. This means that Removable Storage Management treats CD-R, CD-RW, and DVD-R media as read-only media types even if you add them to the Ntbackup media pool.