thunderway

Perfect. Thanks much for the prompt reply. Super app, here.

Checking to see if I've guessed this answer: Imgburn Dual Layer Option box popped up midst the burn operation for the first time. I don't use DL or know about it yet, so I choose to Ignore. Then Imgburn said the ISO was too large. The ISO (by DVDFlick) turned out to be too large for a single layer disc. Don't know why, it's the first time in 10 discs. I assume then that the DLO box popped up because the ISO was too large for the disc, and so it assumed I was using a DL disc. Right? Does Imgburn normally detect that a DL disc is in the drive, or does one have to specify?