Try this: launch iPhoto with the Option key held down and create a new, test library. Import some photos and check to see if the same problem persists. If it doesn't with the new library then your current library is the culprit.
In that case make a temporary, backup copy of your library if you don't already have one (Control-click on the library and select Duplicate from the contextual menu) and apply the two fixes below in order as needed:
Launch iPhoto with the Command+Option keys held down and rebuild the library.
Since only one option can be run at a time start with Option #3, followed by #4 and then #1 as needed.
Using iPhoto Library Manager to Rebuild Your iPhoto Library
1 - download iPhoto Library Manager and launch.
2 - click on the Add Library button, navigate to your Home/Pictures folder and select your iPhoto Library folder.
3 - Now that the library is listed in the left hand pane of iPLM, click on your library and go to the File ➙ Rebuild Library menu option.
4 - In the next window name the new library and select the location you want it to be placed.
5 - Click on the Create button.
Note: This creates a new library based on the LIbraryData.xml file in the library and will recover Events, Albums, keywords, titles and comments. However, books, calendars, cards and slideshows will be lost. The original library will be left untouched for further attempts at fixing the problem or in case the rebuilt library is not satisfactory.
Give this a go: make a temporary, backup copy (if you don't already have a backup copy) of the library and try the following:
1 - delete the iPhoto preference file, com.apple.iPhoto.plist, that resides in your
User/Home/Library/ Preferences folder.
2 - delete iPhoto's cache file, Cache.db, that is located in your
User/Home/Library/Caches/com.apple.iPhoto folder (Snow Leopard and Earlier).
or with Mt. Lion from the User/Library/Containers/com.apple.iPhoto/
3 - launch iPhoto and try again.
NOTE: If you're moved your library from its default location in your Home/Pictures folder you will have to point iPhoto to its new location when you next open iPhoto by holding down the Option key when launching iPhoto. You'll also have to reset the iPhoto's various preferences.
NOTE 2: In Lion and Mountain Lion the Library folder is now invisible. To make it permanently visible enter the following in the Terminal application window: chflags nohidden ~/Library and hit the Enter button - 10.7: Un-hide the User Library folder.
If the above fails one last test: log into another user acocunt on your Mac and see if iPhoto can launch and operate without crashing. If it can't then a reinstall of iPhoto is warranted. It it can then there's sometihng in your account that's wonkers. Post back with the results.
A few days ago I discovered the solution to this problem for a client using iPhoto 9.5.1 in OS X Mavericks 10.9.4.
TRIED ALL KNOWN SUGGESTIONS BUT NONE HELPED
My client had already tried repairing, rebuilding etc. the iPhoto Library, and I tried OS X's Disk Verify and Repair Permissions plus emptied the cache folder in system Library and in the hidden user Library folder (option-key "Go" menu, Library). None of this helped.
CLUE TO PROBLEM
I noticed several of her iPhoto Book projects each had thousands of "unplaced" photos. In each of those cases, each Book project only had 10-50 "placed" photos used to order the book but thousands of "unplaced" photos. In a Book project, clicking on the bottom-right corner's "Photo" icon-button caused an extremely long lasting spinning beach ball making iPhoto unusable for long periods.
I discovered the problem by clicking once on an existing Book project's name in the left column of iPhoto, then letting go of the mouse with its arrow cursor hovering over the selected Book project name. Within 1-7 seconds, a little pop-up appears listing the total number of photos (placed + unplaced) in that Book project. For many Book projects, the total number was just several more photos than the number of "placed" photos, e.g., a Book with 25 photos showed "(37)" in the pop-up info by the hovering stationary mouse, meaning 37 total photos (placed + unplaced) are associated with that Book project.
...some projects listed over 5,000 (five thousand) photos associated with a single Book project that had only placed 20-40 photos in the final printed book. One Book project had 6,070 and several other small book projects showed over 1,000 photos. In each Book project with a mass of unplaced photos, clicking the bottom-right "Photo" icon-button caused a very long-lasting spinning beach ball, almost certainly because iPhoto struggled to build a huge list of thumbnails for the mass of unplaced photos.
My client didn't understand how to efficiently add photos to a new Book project and was clicking on the pull-down menu in the right column that appears after clicking the Photo icon-button within the Book project. From the menu she chose "Last import..." or other menu choice that added a mass of "unplaced" photos to the Book project.
She didn't realize that after creating a new Book project, she could simply drag an individual photo or multi-selected group of photos or an event or "faces" group from its respective library section and drop it onto the Book project's name in the left column, thereby adding only a small group of "unplaced" photos.
=====Delete mass of "unplaced photos" within a Book project
This works best for cleaning up smaller number of unplaced photos from completed Book projects.
Problems with solution:
- if the number of unplaced photos is huge, e.g., 6,070, the list of unplaced photos won't appear for a long, long time if ever.
- even if the list of unplaced photos finally appears, there's no way to select more than one thumbnail at a time, i.e., command-a for Select All doesn't work, nor do shift-clicks and command-clicks for multi-item selecting. You must click one photo then tap the "delete" key on your keyboard repeatedly and fast for this to be practical (note: delete key presses are cached here (meaning accumulated until it catches up processing them later); tapping the delete key like mad then waiting for iPhoto to catch up takes lots of patience.
====Delete an entire existing Book project containing a mass association of unplaced photos
This is practical if you've already printed your Book project and no longer need it. My client chose this method for Book projects with a mega mass of unplaced photos.
Problem with solution:
- for incomplete Book projects in progress with a mass of unplaced photos, you'd have to start over after deleting the whole thing.
NEED FOR IMPROVED IPHOTO FEATURE(S)
(1) The existing "Clear Placed Photos" button within a Book project might be useful, but it'd be even better to also have a button to "Clear Unplaced Photos,” and this button should be available outside of the section that struggles to display thumbnails of large numbers of unplaced photos. Clicking "Clear Unplaced Photos" would do the trick.
(2) An additional iPhoto behavior might help: iPhoto should warn with an option to cancel when adding a mass of photos to the "unplaced photo" section if the number of photos exceeds ??? (400??).
(3) Add another choice to iPhoto’s special startup Administrative window (Repair, Rebuild, etc.): "Remove unplaced photos from existing projects. (Doesn't destroy any photos in Library)"
That is an interesting observation about the number of unplaced photos. Be sure to send feedback to the Apple developers.
I noticed the slow startup of iPhoto with the spinning wheel frequently when products are selected - books, and also slideshows.
I doubt however, that this is the reason for the problem discussed in this thread, since the problem happens even with an empty iPhoto library, if you look at this post: in response to yamahanytro