Apple Aperture 3.6 was the final update for Apple's professional photo editing and management software, released primarily to ensure compatibility with OS X Yosemite.
Since Aperture is obsolete, consider migrating to: Apple Aperture 3.6 -ked-.dmg
Rebuild/Repair Library: Hold Command + Option while launching Aperture. A window will appear offering to repair permissions, repair the database, or rebuild the library. Apple Aperture 3
Since Aperture is no longer updated, many users migrate their libraries to modern alternatives: Smooth transition from Aperture to Capture One Pro 9 Adobe Lightroom : A popular and feature-rich photo