[isaacszy]

OK - back again, a day later. In the meantime, I have downloaded the latest build (6b) and replaced the version in my Applications folder. That didn't really seem to work.

I also tried shutting down all network sharing, and shutting off any network connections, just to be safe (this was all before I got your last steps of advice, Lizard.)

So after deleting the omniplan preferences file in Libarary/Preferences, OmniPlan opens perfectly, launching a fresh plan with task 1 just staring at me. I also tried opening some of the OmniPlan and MPP files I had on my hard drive, and they opened instantly and cleanly. Thanks.

To answer the question, yes, I'm running an (Intel) MacBook 2.0 Ghz with 1.25 GB RAM. I also did try the waiting thing, but that's no fun. Because hey, in the immortal words of Tommy Lee, "we're not here for a long time, we're here for a good time."

I don't know what caused the crash. Maybe a plan that was too big. Maybe a combination of fast-switching between apps. But it appears, for now, that this problem can be cured by deleting the Preferences file from the Library. Thanks Omni.