Unknown build error, ‘Item has already been added. Key in dictionary: ‘xxx’ Key being added: ‘xxx”

I got this message today, it was interesting that it only happened the first time I try to build after a change in the code, and every time when I hit build for the second time it worked. The problem was that somehow the visual studio project file have duplicate items, in my case it was an image. So just edit the project file and get rid of the duplicate item, that’s it.