When a DVD player displays a bad disc error, the cause could be a damaged disc. The DVD player itself may also be the cause of the problem.
In order for a DVD player to function, it needs to be able to read the data written into the disc inserted into the player. If a disc is scratched or damaged, the DVD player will be unable to access the information from the disc and a bad disc error may be displayed onscreen. If the disc is dirty or smudged with fingerprints, a simple cleaning may correct the problem. Wiping the disc in a straight line between the hub and the rim with a soft, dry, lint-free cloth is recommended. Strong cleaners, acids, solvents or abrasives should never be used. Compressed or canned air must also never be used on the disc because extremely cold air can cause thermal stress to the disc. If the disc has grime or dirt on it, isopropyl alcohol can be used to safely remove it.
To determine if the problem lies with the disc or with the DVD player, the DVD player should be tested using several different DVDs. If the bad disc error occurs with more than one disc, the problem could be the result of a malfunctioning DVD player or a dirty lens. If cleaning the disc doesn't eliminate the problem, using a DVD repair kit may help repair the player.