How serious is a bug? How about not saving your work? That makes the program effectively useless. In fact, it has negative use since it's wasting your time! iMovie '09 is supposed to save your work automatically - there are no save options - BUT IT DOESN'T! Fortunately, I finished a satisfactory version of my work and exported it, because when I opened iMovie today, some of my changes were gone! I pity the people who worked for hours and lost their work. This makes me feel that even with automatic saving, you need a manual option.
The important part is the comments
Looks like iMovie '11 has the same problem! I'm steering clear of Apple software for a while.
Some people say iMovie '09 8.0.5 works, but I'm using 8.0.6, and I just came across this problem. Now searching for a way to "force-save".