Home Forums Peripherals & Multimedia Audio, Video, Photography iPhoto 9.4.2 hangs at start up (revised)

iPhoto 9.4.2 on MBP late 2007, OS 10.8.2
On start up, IPhoto goes to repair mode and starts to repair permissions and rebuild the database. This takes ~an hour to complete. Until this is done, no other iPhoto functions work i.e. scrolling through library, printing, importing, etc. Activity Monitor shows iPhoto using about 25% CPU capacity during this time. Non-iPhoto functions work fine.
640 GB HD, 304 GB used.
What next, please.
Thanks
Rick in Maine

OK, I've messed around with iPhoto more. When I "rebuild the database" from iPhoto First Aid it clears up the problem...until I quit and restart. Then I have to rebuild the database again before I can use iPhoto.