Breakpoint Failure 

If two or more source files in the project have the same name, the debugger might have trouble determining which file the breakpoint is set in. This often happens if you create a module with the same name as a component of the Debug library you are linking to.

To fix this problem, enter the full path for the source file. You can change the file pathname on the File Breakpoint dialog box. For more information, see How to: Edit a Breakpoint Location.

In other cases, the debugger might not locate the source file corresponding to a breakpoint, even though the source file exists. This happens if a source file has changed and the source no longer matches the code you are debugging. If you want Visual Studio to display source code that does not match the version you are debugging, clear the Only use source code that exactly matches the original version option in Debugging node of the General category in the Options dialog box. You can also bind the breakpoint by checking the Allow the source code to be different from the original version in the File Breakpoint dialog box.