CD rot (or DVD rot) is a phrase describing the tendency of CD or DVD disks to become unreadeable due to physical or chemical deterioration. The causes of this effect vary from oxidation of the reflective layer to ultra-violet light damage and debonding of the adhesive used to stick the layers of the disc together.

Types

On CDs, the rot becomes visually noticeable in two ways:

When the CD is held up to a strong light, light shines through several pin-prick sized holes.

Discoloration of the disc, which looks like a coffee stain on the disc (see also CD bronzing).

In audio CDs, the rot leads to decreased audio quality, chatter, scrambled audio, and static.

A Philips press officer has declared CD rot to be an isolated problem affecting only an "absolute minority" of cases. PDO has offered to replace any discs affected by CD bronzing if supplied with the defective disk and proof of purchase. However, according to the website of one of the affected record companies, Hyperion, PDO's helpline was discontinued in 2006 after a change of ownership, and defective CDs are now no longer replaced by the manufacturer, although some of the affected record labels continue to offer replacements.