Why don't my players show up when I try to attach my debugger?

I’ve been trying to attach my MonoDevelop debugger to a built Unity player, but I’m having no luck at the moment. I can successfully attach to the Unity Editor with no problems, however, when I click “Attach to Process” and MonoDevelop lists processes, the Unity Editor is the only one that ever shows up. Web players and standalone Windows players never seem to show up in the list.

I have ensured that “Development Build” and “Script Debugging” are checked each time I’ve attempted this. Is there something else that I’m missing?

Did you set the Release Channel to Development by right clicking on the unity player in your browser and seeing that option in the context menu?