Ok - I've made two coasters today on my iMac 27" core i7. I am using Verbatim DVD +R DL blanks and utilized Disk Utility to make one coaster (copy to a .CDR and then burned) and then used Toast 10 to write IFO files. The DVD will "run" but looks and sounds like a satellite tv signal in bad weather - choppy all over the place. This happens on 4 players - two separate laptops, an xbox 360, and even the original iMac 27" I used to write the DVDs. I have had no problems whatsoever writing single layer DVDs (even using old Comp USA blanks!) and playing them on aforementioned players. Anybody have any success writing DL DVDs? If so, what brand of disc did you use? Did you reduce speed to 2x writing? Help - I don't want to create any more coasters!