why has the "Restoring from ICloud..." issue on large photo libraries not been addressed????

Just a thought - if you are having this problem since Catalina and there are items in your Photos Library, that you imported before e the upgrade to Catalina, you may still have incompatible items in your library, that can no longer be processed after the upgrade. There may be videos in your library, using an unsupported codec, PDF files, scanned photos using unsupported codecs or color sync profiles, Live Photos created with third party apps, even audio files saved to Aperture and migrated to Photos. Also, a single item imported as Referenced can block the syncing with iCloud Photos. The "Unable to upload" smart album can point out some problematic files, but it does not suffice.

A smart album searching for the filename extensions can help to find candidates to check.

The only safe way I found to detect the culprits has been exporting the suspicious files and importing them in small batches into a second library created for testing. All items that needed converting to a different format gave a warning, when I tried to import them into my test library. (About legacy media in iMovie for macOS - Apple Support)

• First I exported all videos, tested them by importing to the test library, then converted all videos to HEVC that failed the test. I used with QuickTime Player on a Mac running Mojave for the conversion. Without a Mojave Mac you may need to use third party software like HandBrake or GraphicConverter to convert videos, that are no longer supported since Catalina.
• Next I tested all Live Photos the same way. I had to remove and recreate quite a few Live Photos, that had been created from videos in a legacy format.
• I also checked all photos that have been shared to me by others and have not been taken with one of my cameras or have been edited with a third-party editor.

Your test library, with only items that have been imported without any error message, should give the message "Curation complete" below the "Library > Days" tab. As long as you are having problematic items in a library you may never be seeing "Curation complete" for this library.

After cleaning up all legacy items replace them with tested, converted versions in your main library.

My apologies to themunger for breaking in on this thread but I'm going to respond with answers to your questions in the hopes you may have some useful information because so far, nothing seems to work in regards to signing in and out or stopping/restarting iCloud:

1. My sync status indicates indicates "Updating" and has for several days. My photos library on my Monterey iMac claims 45,920 images and 360 videos. The photos are mix of Nikon and Sony raw files, jpegs, tiffs, plus my iPhone images. Photos on my iPhone, iCloud web, and iPad show only 13k images.
2. The library is stored on a brand new 4Tb WD Easystore formatted APFS. The previous library was stored on an older 5Tb WD Easystore formatted Mac OS Journaled.
3. Initially, I had the Unable to Upload folder which disappeared after one of several attempts to start/restart iCloud photo storage. I created a Smart Folder for "Unable to Upload to iCloud" which shows no images. Regardless, the difference between my Mac-based library and iCloud is over 30k image

I'm about to give up on Photos as a means to manage my photo libraries as this is not the first time I've had issues with iCloud. I like Photos even though it pales in comparison to Aperture (don't get me started!). Photos with iCloud is a great platform for sharing photos with family and friends and over the years some great extensions have been developed which make it a strong raw conversion tool, but these constant issues which have been creeping in recently are getting more than I want to deal with. There are other ways to publish photos over the internet but unfortunately no systems that are as closely integrated with the Apple ecosystem as Photos. It's a shame!

Any suggestions are greatly appreciated!

Hi

Apple are not here - you are stuck with us, just users like you...🙃

What does the sync status say at the bottom of your all photos view?

Where is your library stored? On the system drive or external? If external, what is the format?

Do you have an "unable to upload" folder, or if you create a smart folder, with the condition "photo - is unable to upload to iCloud" does it show anything?

Sync to iCloud is slow - I think you are going to have to wait a little longer. For reference, my 5000 image 50GB library took a full 48 hours. If yours goes at the same speed, you could be looking at 2 to 3 weeks, 24/7.

Leave the mac on 24/7 connected to power, photos open and sleep disabled. Also be aware that signing out/in or stopping/starting icloud restarts the full sync process from the beginning.

Also be ware that the status indication will not update for long periods - especially at the start of the process as the first thing it has to do is compare the current contents of iCloud with what is on your mac.

If you've done the turn off/turn on trick - be aware that this restarts the process back to the beginning again - it does not help. New library - the same.

Yes large libraries take a long time. (see my comment above about how long my small 50GB library took). Regardless of whether you think it is reasonable, your only solution is to be patient, and let it take it's time. You cannot speed it up, you can only wait. DO NOT start and stop the process, you just make it take longer.

My current state is opening Photos and and getting the "Welcome to Photos...to get started do one of the following..."

If that's what happens when you launch Photos then it suggests that your Library is corrupted, and Photos is not recognising a valid library there - which would explain your other issues.

Syncing, as you've been told, is slow. Very slow. If it's too slow for you it is possible to use alternative apps that might meet your needs better, or faster. Or both.

the developer of this app in house should be fired.

Hmmm. Wishing this on people who may have families to feed and bills to pay is not a good look.

If your library only has 9k items then it's not a large library issue.