After updating to Yosemite, I updated iPhoto. Alert said to convert my library to new iPhoto. Then alert said I needed to repair permissions. Then a freeze. Then iPhoto won't find and show my library. How do I fix this?

Question

After updating to Yosemite, I updated iPhoto. Alert said to convert my library to new iPhoto. Then alert said I needed to repair permissions. Then a freeze. Then iPhoto won't find and show my library. How do I fix this? I can see the library icon on my external drive, but it doesn't show as a library in iPhoto. When I double click on the icon, nothing happens. When I choose it from alternate menu, doesn't open. Where do I get help?

Answer 1

Peter
Do you have a back up? What version of iPhoto do you have? Assuming 09 or later:
Option 1
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:
Option 2
Download iPhoto Library Manager and use its rebuild function. (In early versions of Library Manager it's the File -> Rebuild command. In later versions it's under the Library menu.)
This will create an entirely new library. It will then copy (or try to) your photos and all the associated metadata and versions to this new Library, and arrange it as close as it can to what you had in the damaged Library. It does this based on information it finds in the iPhoto sharing mechanism - but that means that things not shared won't be there, so no slideshows, books or calendars, for instance - but it should get all your events, albums and keywords, faces and places 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.  
Regards
TD