Unknown disk, please check disk again.

did you finalize your dvd? also, the following describes the answer to alot of dvd error problems.

i did everyting today to fix this. bought new dvds, name brands different, tried finding codes, called the number. trust me. try this. clean it. thats All i did. cleaned it with a dvd cd cleaning disc, the one with two little brushes on it, nothing special, ran it until i heard the beep, popped my dvd in, they all worked. everyone, im still recording. i ran it about four times. now, if you tried to burn a dvd, and got the error, throw that dvd away. because i tried about ten dvds. after i fixed it, THOSE dvds were no longer usable. dont know why. hope this works.