I had to go to a DVD backup for images after a HD failure. This is a DVD- burned on this machine. disc was burned sometime in 2010. When trying to open some images and folders the machine just sits, no joy. Will not open some images or folders. Cannot import images, etc. iPhoto gives message after 30 minutes that some files are corrupted. Question is not so much how to retrieve those images (though that would be nice) but what went wrong? When I burned the disc it verified fine. Is this a problem with the burner drive (same drive all these years)? Should I replace the drive itself to prevent future problems? If so - suggestions. This is internal optical bay 1 on my Mac Pro. OEM drive, made by Pioneer IIRC.