We received some data on a DVD which had an open UDF session - DVD session had not been closed. On Mac and on Windows explorer, the disc displays as empty. Nero Burning Rom's Disc Info showed the open session, but my DVD writer has some writing issues, so I was unable to close the session with Nero 8. The writer which is working is on a machine which has Nero 6, which does not have the Finalize session option. Googled for closing UDF session, and videohelp forums pointed to ISO buster. I had ISO buster, which was able to extract the files with no issues.