I have the same problem when trying to export a 720P movie to iTunes. Reboot did not help nor did renaming the project. I have an older MacPro with dual 3.0s, 11 Gb Ram and slightly less than 1Tb free space on the boot drive. This is a software issue, not a hardware problem. Apple please fix the myriad of problems with iMovie 11. My productivity has ground to a halt with my 4 month old iLife Software. How did this software ever pass muster!!!!! I can't believe anyone would purchase the new version of Final Cut given the horrible product you've included with the last iLife Set. This is an example of why I left the Microsoft Windows community. SHAME ON YOU!!!!!! I usually create 4 to 5 movies a month for the flying community I live in. I have completed one since January, and it was a mess due to software glitches. My attempt to re-render an old iMovie 9 creation has been met with failure. I have projects backing up and really have no desire to finish them or create others as iMovie 11 is no longer fun since it is broken. I'm tired of iPhoto 11 and iMovie crashing or not working and the reason for spending more on an Apple product no longer exists. Outdated expensive hardware and buggy software. Time to sell my APPL stock like Bob Mansfield, You're ignoring your core supporters and are living off the hype of the iPhone/iPad. The poor economy has allowed your "halo effect" to endure many recent short-comings - (Mobile Me (how slow and expensive can it be to stream a personal home movie - but don't worry you don't need Blu-Ray)), Mail (why do I keep getting duplicate emails in my drafts folder? and why is it always losing my password - just like Mail on my iPhone), Never providing a stable video card for 2006 Mac Pros, Crippled iPhone 4 for Verizon, no iPad Flash support, iLife Crapware)............where's the Tylenol!!!!! I need it since I promised an iMovie project for a friend's memorial that I am now unable to deliver.