Photos Library Problem

Does your new iCloud Photos Library already have all the photos you want to see in iCloud and on all your devices?

You can only view your shared albums in your iCloud Photos Library. Do not even try to view them in your other, old library. You have to make up your mind, which library to use for any iCloud services. As laleef pointed out, this library has to be your system photos library as well, and the system photos library is special:

• Your System Photo Library is the only library that other applications can access, for example Mail. external editors, etc.
• Only your System Photos Library can be enabled as your iCloud Photos LIbrary or sync with Shared aAlbums.
• Your System Photos Library needs to be available, as long as you are signed into your user account, so the background processes can update and analize it. If your System Photos Library is on anexternal drive, you have keep this external drive plugged into your Mac, while you are signed into your user account, even if you are not planning to open Photos at all.

To get your old photos from your old Photos Library into your new Photos Library, you could import the missing photos directly from the old library. This will import them as pairs of the original and the edited versions, so you can revert the adjustments individually. The keywords will be missing, however. But try this:

• Open your current iCloud Photos Library in Photos.

Use the command "File > Import" and select the old library for importing, as described here:

Import photos from another library

• Photos will now show you all photos in the old library, that are not already in your current iCloud Photos Library. Select all "New" photos for import.

You mentioned, that you are not seeing your iCloud Photos on your iPhone. Have a look at the status bar in Photos on your Mac and in Photos on your iPhone. Check the status of your library in Photos for macOS - Apple Support

And check, which photos have made it already into iCloud by viewing your iCloud Photos Library in the Photos.app at www.icloud.com in Safari on your mac. This will tell you, if your Mac is uploading to iCloud or not, or if the problem is with Photos on your iPhone.

Hey there,

You can use iCloud Photos, Shared Albums, and My Photo Stream only with the System Photo Library. If you choose a different library in Photos without designating it as the System Photo Library, the iCloud tab in Photos settings is disabled.

Here’s the instructions for this issue:

1. Quit the Photos app.
2. Hold down the Option key and open Photos. One of the photo libraries is already designated as YourLibraryName (System Photo Library). 
3. Choose the library you want to designate as the System Photo Library.
4. After Photos opens the library, choose Photos > Settings (or Photos > Preferences) from the menu bar.
5. Click the General tab.
6. Click the Use as System Photo Library button.
7. If Use as System Photo Library is grayed out, the current library is already set as your System Photo Library.

All The Best!