Sometimes users find that iPhoto doesn’t work on Sierra. To macOS Sierra and found that the iPhoto app. Apple store to download the latest. I hear Apple no longer have iPhoto for download at the app store any more!! But some people have tried work around by copying iPhoto from older Mac. Use the Mac App Store to download and install macOS High Sierra on Mac computers that meet the system requirements.
Switch to Photos from iPhoto If you didn’t update to OS X v10.10.3 or later, then when you update to macOS Sierra, the Photos app is installed automatically. Photos includes many features that aren’t available with iPhoto. For example, you can see all your photos on all your devices with iCloud Photo Library and have your photos organized the same way on your Mac and your iOS devices. When you first open Photos on your Mac, your photo library is upgraded. The upgraded library is compatible with both Photos and iPhoto (if installed), but any changes you make in Photos won’t appear in iPhoto, and vice versa. If you previously had iPhoto on your Mac, it’s still on your Mac. You can open it from Launchpad or from the Applications folder in the Finder.
However, it’s strongly recommended that you use Photos instead of iPhoto. For more information about the Photos app, see Photos overview. Mac & Devin Go To Highschool Download here.