Can I prevent the CLR from optimizing away debugging information?

I've encountered this same problem before, and it's invariably due to the fact that Debug mode has been turned off in some way. Try checking each of the following:

1. The current build configuration for the solution and the appropiate project(s) is Debug.
2. In the Build tab of the property pages, the Optimize code checkbox is unchecked.

If this is all correct, then I recommend you paste the text written to the Output window here so can we can potentially spot any more unusual cause of the issue.

Make sure your arent trying to debug your release build. All of these compile settings set behind these configurations. The debug version is one for debugging ;-)