Missing photos

Unlike Glenn, I conduct all my file management within the Organizer.  In your situation, I would first want to know how the files became missing.  As Glenn indicates, the possibilities include moving, deleting or renaming the files outside of the Organizer.  If you can tell us how the files may have become missing, we can give you a better answer on how to reconnect them in your catalog.

For many just do the following. 


Undelete them.
Put them back where they were originally.

I assume that you "did something" outside of organizer-- me? I delete all my desktop stuff once a month, after I make a backup copy- I just ignore the missing image stuff in organizer.   

Some users just move stuff around manually all willy nilly (like I do- i have "my system" which works ifne for me), forgeting that they have organizer monitoring folders.