does exactly what was required, although Sony warned AGAINST using any cleaning disc! I have a Sony RDR-HXD890 hard disc/DVD recorder,about 4 years old. The DVD recorder had failed and would not recognise any DVD (prerecorded or blank). Sony sent me a CD-RW for updating the software, but this disc could also not be recognised - total waste of time! but after using this cleaning disc all problems are solved - for just a few pounds - where Sony would have probably charged a small fortune for repairs!!