Microsoft Visual Studio 2012 cannot set breakpoint in c# file

Question

I have Microsoft Visual Studio Professional 2012 installed, version 11.0.60610.01 Update 3.

When debugging a c# (.cs) file Visual Studio gives me the following message

Answer 1

I have encountered a similar issue and I resolved it by exiting Visual Studio and deleting the .suo file from my solution folder.

This file is recreated when you open the project again and it is not harmful to delete it.

The .suo is used for storing the layout of your solutions, the breakpoints you've set, the tabs you had open, etcetera. I am not sure why this worked but my logic was that Visual Studio thought I was trying to place a breakpoint in a location different to where I was actually placing it.