HT5037 Upgrader won't upgrade my library?

Question

When I try to open my iPhoto library, it says that it first needs to be prepared by the iPhoto Upgrader. When I use the Upgrader it says the library does not need to be prepared, but it still won't open. How do I resolve this?

Answer 1

By moving your iPhoto library between Macs with Dropbox there's a good chance the library was damaged due to the fact the Dropbox doesn't have servers formatted properly for iPhoto libraries, OS X Extended (journaled).
Try connecting the two Macs together via Firewire (Target Disk Mode,  Transferring files between two computers using FireWire), LAN and copy the library directly from the old Mac to your new one.  Or use an external HD formatted properly to transfer the library.
Otherwise, if the other suggested fixes fail to get you back up and running try the following with the library that is more likely to hold all of your image files (even if it can't be opened with iPhoto):
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.