I don't think it will be a single file size problem Squarebear, a 2GB MP3 would be about 35hours long!!
What software are you using to burn with dwil? (i'm wondering has it a setting for 8cm and 12cm disks, 1.77 is possibly about what you can overburn a 8cm DVD to)
I've got a single mix mp3 of nearly 1GB so I guess it would be possible, unlikely though :)
dwil,
yep please do check the settings in your software, it's always a good place to start ;-|
if you can't find any thing, then, as your just backing up try some different software too, you only need to copy the folder all your music is in to back it up. try this instead.
I seemed to have solved it. I'm now using the 'drag-to-disc' facility rather than 'copy files to disc' which I've used before for data transfer. The d to d seems to use all 4+Gb.
Thanks for all your help & suggestions.