Sometimes, when searching in Visual Studio (all version since 2003 at least) you get this message:
No files were found to look in.
Find was stopped in progress.
It cannot find any match for the search criteria, even if there are thousands. And it displays that message immediately after pressing Search. You can search again (for something else), restart Visual Studio, restart Windows, it will do no good. The message will always be the same.
What’s the cause? I don’t know, but I’ve noticed this happens when I search for something while the solution is building.
What’s the solution? Well, pressing CTRL + SCROLL LOCK does the magic. You don’t have to have anything (search dialog) open. Just press those keys in Visual Studio and serach will be up and running.