Aperture Stuck Generating Preview

Every time I open Aperture I get the "Processing..." spinner indefinitely. When I open the Activity console I see that it is stuck generating a preview. I deleted the offending photo and restarted (I have to Force Quit every time) and I find that it is stuck on a new photo. I've deleted about 15 photos now and I feel like I'm just playing whack a mole. Some of these photos have been in my library for 3+ years, so I don't think there's anything actually wrong with them.

I have done the double-click+cmd+option trick to repair permissions, repair library and rebuild library, none of which seem to help. I've removed my Facebook account in case it was pulling a bad photo from there. I also attempted to open the library in iPhoto, but that app just starts beach-balling.

I'm using Aperture 3.4.3 on OS X 10.8.2. Any suggestions would be greatly appreciated.