I have a simple catalog, just one folder. Every few days, a subfolder gets added, with one text file. Searching any file works fine up until about a week ago. The 5 files and folders added since then won't show any content in the search. I don't see anything in the Application or System event log that would point to what's wrong. Help?
Check the permissions on the folder, iirc the Indexing service needs to be able to access that location, and it's possible to remove the necessary permissions.
You can also try rebuilding the index, in case it's become damaged in some way.