The breakpoint will not currently be hit. No symbols have been loaded for this document.

Doug Butscher’s blog post about the subject was able to get me debugging again in one of the Visual Studio 2010 projects in my solution. As he noted in Step 3, the Modules window indicated that the Symbols were loaded.

I stopped the debugger, deleted only the obj folder, and restarted the IDE. That was enough to fix it for me.