Depending on how old or new the disk is, you should first try to clean the disk itself with some proper disk cleaning material you can find a suggestion in our [[Sony BDP-BX620 Troubleshooting|troubleshooting page.]] Otherwise I would buy a disk cleaning set from your local supermarket. If this does not solve your issue then your disk reader can be dusty or just malfunction you can buy a disk reader cleaner at your local supermarket. If these do not help again check out the troubleshooting page link above.