I have this DVD-A04 unit. When you cancel a DVD-RW in the making process, or crash, or shut down without finishing it first, it makes something to the disk that cannot be recovered even if you try performing a full erase. Well theorically it shouldn't do this so my guess is it's an hardware isssue like it can't read the track and craps up and doesn't want to delete it afterwards. It detects the DVD-RW after 3-4 minutes of the green light being on and the drive scrubbing on the disk, but won't erase it properly, or say this media cannot be erased. I tried instant dvd, tried nero latest version, nothing work, full erase, quick erase... sometimes it will do something (starts like 3 minutes later after the erase command got issued) but when I open and reclose the tray, it still do the same thing. Tried 2 different machines, tried disabling UDMA to PIO mode, got the 1.33 firmware, I guess what would be needed is a low-level "blind" erase tool but this doesn't seem to be available. Any other hints ? the Dvd worked fine before, I'm sure it's not defective media as I reproduced this problem... (princo DVD-RW, I know it's not the best but it should do the work). Thanks.