Rank: Master
Rating: 88%, 11 votes
Let me clarify something.
mathers9312 asked specifically,
"cant copy _copied_ dvds..."
If you're attempting to copy _copies_ of commercial DVDs, don't. Unless you own BOTH the original AND the copy already made, I doubt you have any imaginable right to make a copy of the copy (and if you owned the original, why attempt making a copy of the copy, anyway?).
That said, IF the original question was a simple misstatement and you are simply attempting to copy DVDs you legally own for purposes of archiving/backup, here are the culprits I'd look to:
1. Parameters in your burning software are mis-set. Try lowering the burn speed, turning off write verification (sure, you might thereby burn a coaster, but in some cases it does help to turn off verification).
2. Defective media: this could be either the burn media or the original media. Clean the original DVD by wiping with a soft, clean cloth from the center hole directly to the outside edge. NEVER wipe the DVD is a circular motion around the circumfrence of the media.
3. Defective DVD writer: This could be something as simple as a dirty lens. DO NOT attempt to wipe the lens by hand or blow it clean with canned air. Either of those techniques could affect alignment/mechanical elements. Purchase a CD/DVD cleaning disk kit. WallyWorld and many other discount stores has them at a very inexpensive price.
4. Copy Prrotection on the original DVD you are attempting to copy. Frankly, this sort of thing chaps my gizzard. :-) We all have a legitimate right under fair use to make backup/archive copies of media we have purchased (as long as we do not sell or give away those copies).
http://www.dvd43.com/ is a source for one software application designed to allow folks to make legal copies of CDs/DVDs they have a legal right to make backup/archive copies of.