LRC - "No photos in selected Folder"

These photos have already been imported, but to a different folder than the folder you think they are in. You need to find these photos in Lightroom Classic. Follow all four of these steps in order:

1. In the Lightroom Classic Library Module, on the left, under Catalog, click on All Photographs
2. Turn off all filters (Ctrl-L once or twice)
3. Turn off all stacking (Photo->Stacking->Expand All Stacks)
4. Search for at least one of these photos by file name using the Lightroom Classic Filter Bar

Let us know what you find.

This could be caused by a corrupted 'Catalogname Helper.lrdata' file in your catalog folder. Trash it so Lightroom Classic rebuilds it. See if that solves the problem. If it does not, then resetting/trashing the preferences is the next thing to try. https://www.lightroomqueen.com/how-do-i-reset-lightrooms-preferences/

It appears that my photos are part of the catalog but Lightroom Classic can't find them? 

I've got several fodlers that say "No photos in selected Folder." When I go to locate the files, the folder is already pointing at the right location and the files are there. If I try to syncronize the folder all of the photos are greyed out saying "This photo has already been imported". 

When I go to all photos and try to search for a filename, I get no results (no filters, unstacked, etc.). How can I resolve this? 

[Double posts merged by moderator. Please do not double post.]