<p>Sometimes while developing in Visual Studio IDE, when you use "Find in Files"  dialog to find something, the search fails and you will see the following message in the "Find Results" window. </p>

<blockquote>
  <p>No files were found to look in. Find stopped progress</p>
</blockquote>

<p>Once this message shows up, all the subsequent searches will result in the same message. Nothing fixes the problem including restarting the computer except pressing <kbd>Ctrl</kbd> + <kbd>ScrLk</kbd>. </p>

<p>What causes Visual Studio to get into this state and is there a setting to permanently prevent it from happening?</p>

I don't think there is anything you can do to prevent it.
It seems to occur after I have stopped a build with CTRL+Break...Maybe I am pressing CTRL+Scroll Lock during that time???
I have only had it happen to me 2-3 times, and that was several months apart.
What he is saying is that occasionally when performing a search within Visual Studio you get the mentioned error message. Even though you know there is stuff to find. It is some weird state that Visual Studio gets into. If you press the (CTRL+Scroll Lock) it will 'fix' the issue.