I am unable to migrate from iPhotos 8.1.2 to the new Photos app. I recently updated from Mavericks straight to El Capitan (bypassed Yosemite). All the other apps are working well, with the exception of Photos. It gets hung up at 24% and will sit there for over half a day. I have an medium-sized library (<1,000 photos), but it is several years old. I have tried to rebuild the library using iPhoto Library Manager without any success. I am looking for ANY solution at this point even one that might erase metadata (but I would prefer to keep it of course). Any and all help is greatly appreciated! Thank you in advance!