Xamarin Android Build Failed “Invalid value for outputAssembly”

Question

A few days ago my solution seemed to work fine, but today all of the sudden the Android project doesn\'t build. I get no Error, but I do get the following output:

Answer 1

I had to clean the project, delete the bin folder (just to be sure), then the build failed with the real reason: an incorrect reference.

Someone copied a project dll instead of linking to the project.

Corrected the reference and all was well.