IPhoto (9.6) No longer works after Yosemite Update! Please Help. The error message I get is below.

Question

Error Message:
"Your photo library is either in use by another application or has become unreadable.
Shut down and restart your computer, and then open iPhoto again. If the problem persists, try rebuilding your photo library. To do this, quit iPhoto, and then reopen it while keeping the Option and Command keys pressed. You can also try restoring your photo library from a backup."
I have performed the instructions above with the exception of the restoration from a backup.(Option/Command no longer yields a menu. Just the error message again).  Really hoping there is a fix outside of the restoration since I have neglected to back up for some time.
P.S. I see that this is happening to others....I have another Mac to update to Yosemite and fear the same results.

Answer 1

Every time there is an update to anything someone somewhere has an issue. That's why backing up prior to updating is so important.
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.