where did my shared albums go from my Mac ?

Hi there NewbookGH,

If you're not seeing Shared Albums on your Mac, start by checking the items listed below:

Before you begin

1. Update your iPhone, iPad, or iPod touch to the latest iOS or iPadOS, your Mac to the latest macOS, and your Apple TV 4K or Apple TV HD to the latest tvOS. If you have a Windows PC, update to Windows 10 or later and download iCloud for Windows.

2. Set up iCloud on all of your devices.

3. Make sure that you’re signed in to iCloud with the same Apple ID on all of your devices that you want to use with Shared Albums.

Afterwards, follow this guidance to be sure Shared Albums are turned on for your Mac:

* On your Mac, open the Photos app. From the menu bar at the top of the screen, choose Photos > Settings. In macOS Monterey or earlier, choose Photos > Preferences. Click the iCloud tab, then select Shared Albums.

You'll find this information and more details here: How to use Shared Albums in Photos on your iPhone, iPad, and Mac - Apple Support

Take care.

Make sure Shared Albums are checked in the library's iCloud settings pane:

It may have gotten unchecked somehow.