Building in Debug gives me a Release build; I can't get back to Debug. Consequently I had this problem which I solved by unclicking "Optimize code" in project properties: Breakpoint Failed to Bind - Visual Studio 2015
But the root cause seems to be that I'm stuck in Release. I confirmed it with this:
#if DEBUG
stuff
#else
other stuff
#endif
And also in Project Properties in the Build tab it always says Active (Release). How do I fix this?