Apple has just replaced iPhoto with Photos. My LR5 library was linked to the iPhoto folder which now no longer exists. I have tried re-mapping to the new Photos folder but it is a hidden folder and cannot be seen by LR5. I have tried displaying package contents but that doesn't work either. Any ideas much appreciated.
If you are using Lightroom to manage your images I would recommend you take them away from Photos application entirely.
File > PlugIn Extras... Import from iPhoto.
However. If you want to continue to manage with Photos AND Lightroom you can create an alias of the Masters folder (in the package contents) and place it in a suitable location. Lightroom will be able to see this folder in the import dialog.
Locate one of the images that is missing and it should be able to locate the others too. You can then delete the alias.