I've got a new iMac and the latest iPhone '11 (9.4.2) and at random times iPhoto quites while in the background doing nothing, that I know of. Is this a known problem with iPhoto as it seemed more stable on my PPC G5 I was running a few months ago. The last time it crashed it on start it required a rebuild or something. Nothing was lost as far as I can tell. Right now it has around 8300 photos, 8.7Gb in total size.