I don't use Nero, but are you sure that's not UDF? There doesn't seem to be much associated with Nero and UDC. UDC could be Universal Database Converter, UDF is Universal Disk Format. If Nero is like Adaptec/Roxio, you can't add more data to a disk if it's had a record session permanently "closed out". With Roxio I think a multi-session disk is drag-to-disk, which can be "ejected" with the option to add more data later, or ejected and closed out so no more data can be read. Are you sure the CD's you received were closed out so more data could be written to them? There's also the possibility that Nero and other burning software may not be compatible. If the CD's were recorded using Roxio, Sony, or other, they may not be able to be seen properly by Nero. Again, I don't use Nero so I don't know for sure. You don't say if this is CDR or CDRW media. One thing I do know for sure; you cannot delete something from a CD-***R**** disk and reclaim the space as you can on a HD or floppy. That's only possible with RW media. You can also try to see if you can do anything with them using XP's Native burning software. -Clint God Bless Clint Hamilton, Owner http://www.OrpheusComputing.com http://www.ComputersCustomBuilt.com ----- Original Message ----- From: "David Grossman" I've had some interesting experiences trying to burn CDs with Nero 6. 1. I tried to add data to multisession CDs that I received. In some cases I received an error message that the disk was UDC, so I could not add data. What is UDC and why can’t I add data to UDC disks? 2. I tried to add data to a multisession disk, but Nero said that it would not fit. I removed some data but received the same message. The third time I tried, after removing a lot of the data, Nero said that the previous data would not be readable under Windows. I tried to see it in a command window - no joy. How can I view and copy the previous data? Is there a way to make it readable under Windows? David Grossman ========================= The list's FAQ's can be seen by sending an email to PCWorks-request@xxxxxxxxxxxxx with FAQ in the subject line. To unsubscribe, subscribe, set Digest or Vacation to on or off, go to //www.freelists.org/list/pcworks . You can also send an email to PCWorks-request@xxxxxxxxxxxxx with Unsubscribe in the subject line. Your member list settings can be found at //www.freelists.org/cgi-bin/lsg2.cgi/l=pcworks . Once logged in, you have access to numerous other email options. The list archives are located at //www.freelists.org/archives/pcworks/ . All email posted to the list will be placed there in the event anyone needs to look for previous posts. -zxdjhu-