I'm not sure if this is the what is causing the problem in my case. I start with an .iso file. I'll use an .iso downloaded from MSDN as an example. Microsoft provides a SHA1 and CRC32 hash for each .iso. The .iso matches both hashes. I then burn the .iso to a DVD+R using imgburn. If I check the disc itself, the hashs still match that of the original .iso. If I extract the disc back to an image using MagicISO, the new .iso image has the correct hashes. If I extract the .iso using imgburn, the new .iso has incorrect hashes. If imgburn is padding the image when writing it to the DVD+R, wouldn't the hashes of the disc itself and of the .iso that MagicISO creates also be incorrect?