Visual Studio 2015 project no longer runs in debug mode

Question

This is what I get even when I run in the Debug configuration:

The way I got this to show was by enabling "Just My Code" and warn if there

Answer 1

This has happened to me on a couple of projects too. I reviewed my build settings, as suggested by stuartd. However, 'Optimize code' was not enabled in my build settings. So I enabled it and saved the project. Then I unchecked it and saved again. Problem solved.

There's some kind of bug that causes the --optimize+ flag to be passed to the debugger. Enabling it and then disabling it is an easy workaround until the bug is fixed.