The problem can occur due to a temporary glitch in the Windows Photos app. Also, corrupt system files and app files are another primary reason behind the issue.
Try adding the location of those Network folders or remove then add them again to see if they show up in Photos.
This sounds like an indexing problem. Select Settings from the Start Menu.
Search Troubleshoot in the search box.
Scroll down to find Additional troubleshooters.
Under the Find and fix other problems section, select Search and Indexing and then click the Run the troubleshooter button
Hope this resolves your Query !!
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