I have been burning 4X DVDs at the 4 hour setting using high speed dubbing (the programs are coming from chaptered recordings on my HD.) I am able to burn and finalize the discs fine and play them back on the unit (and on another standalone Panasonic DVD player), but when I insert them into my Mac, I am only able to access and play the first title (and all of its chapters) on the disc. Usually, I am burning just two titles, but I can never view the second title on the Mac. And in the menu (on the Mac), there is no thumbnail, just a black box highlighting the first title.
Panasonic was, of course, no help. They suggested I try different DVD Media. I've used two different makes.