I recently burned about 20 DVDs to get space back on my machine. Afterwards I was trying to get some of the files off to work on them, and I get the error:

"Cannot copy [filename]: Data error (cyclic redundancy check)."

It happens only on some of the discs, and always with the last file or the last couple files. I installed one of my old DVD drives to see if the drive was having problems, but it didn't work. What causes this, and is there anything I can do about it?

I have given up using DVDRs for backup, for just that reason. They are NOT as reliable as CDRs...not even close. I have never had a CDR fail on me, but I have lost quite a bit of data recently because of relying on DVDRs and having them fail, and have sworn off them forever.

I think it's most likely the combination of my burner with this media. I've been able to read all the discs I made with the media I used to use, but have been pretty hit and miss with this new stuff.

So nobody knows a way to get the information off?

I remember getting similar errors with a combination of cheap burner+ cheap cdr mediia. In that situation I wasn't able to recover the data.

One of the things that worked a little bit for me was to make a disc image and then mount and read the disk image directly from the hard drive using Alcohol 120. I was able to get some more data that way, though some it was still corrupted.

A CRC fault means that the algorithm most likely to recover your recorded data has not been able to. Sorry - you're knackered.

Moral of story: Don't delete until verified.

Yeah, I could have sworn that I verified these discs. I might not have, though. Which of these methods is sufficient, or are both of them fine:

-simply copying the files back to the machine
-dragging them all into mplayer and fast forwarding through them to see if they all read

Here's another thing I'm worried about, though it does give me an explanation for all this. I looked at all the discs that were giving me problems, and at closer inspection, the discs are pretty badly scratched. So, at least I can be fairly certain that this is what's causing the problem, and that the other discs that aren't scratched are okay. But what I can't figure out is when the discs were scratched. Could I burn to a scratched disc? I just don't know what I would have done to scratch it, particularly since the scratches are in a circular pattern around the outer edge. They're pretty severe:

I recently bought some relatively cheapo DVD-R's the came with those exact scratches already on them. I opened the package, looked at the disks, and mailed them back.

If they got scratched after you burned them, then one of the disc cleaners that polish the durface may work. Make sure the one you use though states it can work on recordable media.

That's a good point about the shadow. I know how to tell what area of a disc is burned, but didn't think about how that could be applied to determining the time of the scratching.

The other thng you said that I think I'll definitely do from now on is to do a verification after burning. I hadn't noticed the option in Nero. Or at least I hadn't thought about it since I've been more paranoid about my burns.