I am a holdover user of Aperture despite Apple having abandoned the program. I like the combination of editing tools and essentially a database that can be organized in projects and albums. When Apple pulled the plug I had thousands of photos in my library. I continued to use Aperture with no problems and recently added Luminar to my bag of tricks. Luminar worked seamlessly with Aperture and made photo enhancing an easy task.

Though I know better from prior experience, I bumbled into updating my OS to Apples' latest, Sierra. The upgrenade road was bumpy, but after a day of fooling around with my computer I got Sierra up and running. I launched Aperture and had to hunt for the correct library. When my library showed up I was relieved that it appeared to run normally - that was until I tried to view any of may photos in any view other than thumbnails. None of the other views work making it essentially impossible to do any reasonable editing. It is still possible to use Luminar as a plug in for editing, but the Luminar program has to be running first before you can switch to it using the "Edit with Plug-in" menu item in Aperture.

At this point it appears that I am stuck using Aperture strictly as a database and Luminar for any serious editing. Since my photos are all arranged in the Aperture filing system I don't see any way of preserving the filing system and moving to some other program. I am not an Adobe fan so that leaves Lightroom out. I am told that the Luminar folks plan to add a database feature to Luminar. I am hoping that is not just a rumor.

There probably aren't too many Aperture holdovers on this Forum, but thought I would post this as a heads up to any other users who might be tempted to switch to the Sierra OS.

After reading all the helpful remarks folks made on this thread I think I owe a follow up. When several people suggested that they were still able to run Aperture on Sierra, I did some thinking.

In the process of installing Sierra problems with iCloud developed. Pursuant to Apple's instructions I restarted the computer in safe mode (by holding down the shift key during startup.) The iCloud problems went away but when I started Aperture I could only view my files as thumbnails. None of the other views worked leaving a blank screen.

After reading this thread it occurred to me that perhaps safe mode disabled some of the extensions that Aperture needed to run properly. After a restart in normal mode, the problem went away and at least for the near future Aperture is again running properly.

Many thanks for all the helpful comments.