...with error like: Waiting for reader process to fill input buffer ... Errno: 5 (Input/output error), reserve track scsi sendcmd: no error CDB: 53 00 00 00 00 00 22 7B BC 00 status: 0x2 (CHECK CONDITION) . the medium is blank, so k3b refuses to re-blank it for you. solution that may work is to manually force blanking the medium with: dvd+rw-format /dev/sr0 -force -blank