I have a VERY SIMILAR Problem.
I just bought a new MAcbook Air and I'm trying to import/upgrade my iphoto library (it's on an extermal drive). I've taken a copy of the iphoto library and when I point iPhoto to it (using the option button at the start), it does a thumbnail update which takes a few seconds then it opens up but all my events have blank thumbnails and they either contain no photos in them or they have also photo 'placeholders' i.e. empty thumbnails as well!!!
What system and iPhoto version are you running? Next what format is the EHD? It should be:
If it is and you're running iPhoto 9 or later 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.
Run Option 4 on the library you've been testing. I don't know if this has been suggested but open the library with the Finder as shown below
and check the Masters folder to see if the orignal files are actually in the subfolders. If they are then if Option 4 doesn't help you can continue on with this:
Starting over from scratch with new library
Start over with a new library and import the Originals (iPhoto 09 and earlier) or the Masters (iPhoto 11) folder from your original library as follows:
1. Open the library package like this.
2. Launch iPhoto with the Option key held down and, when asked, select the option to create a new library.
3. Drag the subfolders of the Originals (iPhoto 09 and earlier) or the Masters (iPhoto 11) folder from the open iPhoto Library package into the open iPhoto window a few at a time.
This will create a new library with the same Events (but not necessarily the same Event names) as the original library but will not keep the metadata, albums, books slideshows and other projects.
Note: your current library will be left untouched for further attempts at a fix if so desired.
Do not save any new data on the card to avoid data overwriting.
then you can recover your data on your own with the help of the third party- recovery software.
For my last loss data (yesterday), I used this Mac Photo Recovery software- Wondershare Photo Recovery for Mac. Its Deep Recovery can help you solve your problem.
Get the free trial version from http://software.bigbigsoft.com/data-recovery-mac
This happened to me last night.... I almost cried... 18,000 photos GONE!!! After a ruff nights sleep though I was able to find my original library in iPhoto. This is what I did...
First: Quit iPhoto
Second: Press and hold down the option key and open iPhoto while still depressing option key
Third: This will bring up a list of other iPhoto libraries on the computer. One will be marked as (default)
Fourth: Release option key and click on a different iPhoto from list. This will tell you the location of the selected file.
Fifth: Click Choose. The selected file will open. Repeat steps 1-5 until you find the correct iPhoto library with all you stuff.
Hope this help... it worked for me. Otherwise call apple. They are willing to help and told me they have been able to resolve any issures.
Same deal. Just upgraded to "Maverick" and iphoto was showing a "stop/nogo" sign and I realised iphoto isn't even on my mac anymore. So I looked for my photo library and it is gone. I was about to back up my computer this week and thought " Well maverick is an OS upgrade but its nothing major. I'm sure everything will be fine." Biggest mistake ever. Please supply a fix for this, I see how many upset people there are. This is a pretty big screw up on apples part. I'm a huge fan of backing up before installing things but this one just slipped through my attention I guess. Super bummer. Not impressed. And to everyone who keeps trolling those that didn't back up. Karma will get you one day, so stop with the trolling please.