I have version 8.1.2. When I start it, the Iphoto window pops up but it hasn't loaded any pictures, albums, etc. The rainbow loading disc just keeps spinning and I am unable to click anywhere on the application. I think I have most of my photos backed up, but not the most recent ones. What should I do?
Back Up and try rebuild the library: hold down the command and option (or alt) keys while launching iPhoto. Use the resulting dialogue to rebuild. Choose to Repair Database. If that doesn't help, then try again, this time using Rebuild Database.
If that fails:
Download iPhoto Library Manager and use its rebuild function. This will create a new library based on data in the albumdata.xml file. Not everything will be brought over - no slideshows, books or calendars, for instance - but it should get all your albums and keywords back.
Because this process creates an entirely new library and leaves your old one untouched, it is non-destructive, and if you're not happy with the results you can simply return to your old one.