Originally Posted By: RIck Deckard
I have not tried optimizing storage yet and I don't have a Time Machine backup (I use clones instead).

I will spare you my diatribe on why cloning is an inadequate replacement for Time Machine, but I encourage you to switch to "optimized" images on both your iMac and iPhone. They take up a LOT less storage space, which is particularly useful on the iPhone and you can edit the image on either device and that edit will effect all your devices including the full resolution image on iCloud. To my way of thinking it is a real win-win solution.

Originally Posted By: RIck Deckard
I also have not tried creating an new Photos Library, though I did try repairing it. The repair completed OK, but afterward my Photos window now constantly says "Uploading 74 items" but they never seem to upload.

It sounds as if something is crumbling. Don't wait too long to create your new library, Turning it on takes only several seconds, but populating the new library can take a while and if you switch to "optimized" images that can take many hours, even days to completely settle. One thing more, you probably want to designate the new library as the System Library once it is created.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein