I just burned 4 BluRay coasters (and am now out of BluRays since you can’t purchase inkjet printable BR disks at ANY store on the planet). Image Burn was telling me “Cannot Write Medium - Incompatible Format,” but I wasn’t really sure what that meant. What it should have said was “that file’s too big, dummy.”
Even though Adobe Encore shows the capacity of a disc as 25GB (which is also what’s printed on a BluRay disc), a BluRay disc can ACTUALLY only hold a little over 23GB (sometimes even less). If your Encore project says anything over 23 GB is being used (the big blue progress/capacity bar under “Disc Info”), you’re write is going to fail. Believe me. Anything near that 25GB capacity isn’t going to work.
Heed this advice. It will save you a lot of time, money, and wasted discs.
I usually burn a BluRay .iso rather than burning straight to disc. I then use ImgBurn to burn my BluRay later. It makes it easier to burn multiple copies, and often circumvents problems with Encore. Encore will let you burn an .ISO image up to 25GB, even though that image will not REALLY fit on a (single layer) disc.
Now you know.