I did a three-disk spanned Data/Mac & PC on Friday. The first time it ran, it didn't complete. It got stuck 30% into Writing Leadout on the second disk. However, I think it was probably because my Mac went to sleep at that point. When it woke from the sleep, it remained stuck at 30% through Writing Leadout. Clicking on Cancel had no effect. Cmd-Q and Toast>Quit had no effect. However, Dock>Toast>Quit got Toast to exit.
However, when I rebooted to make sure I got a clean run of Toast again, the shutdown hung on the blank screen just after the spinning "I'm tidying up for shutdown" icon went away, with the internal DVD drive still spinning flat out. I had to press-and-hold Power to get the Mac to complete the shutdown.
When I rebooted and disabled SleepWhenIdle, the spanned Data worked just fine.
Isn't there now an ItMayLookLikeTheMacIsIdleButItsNot call that applications can make periodically to stop this sort of thing happening? Doesn't Toast use it?
MaxBook Pro 2.26GHz, OS X 10.9, Toast Titanium Pro 11.1