Might be worth checking out @bazrush 's blog post here:
Perhaps you need to follow point 6 in case VS is trying to add the JUCE library code to source ?
6. Add a gitignore file to the project root folder that ignores ./Builds and ./JuceLibraryCode. These will be rebuilt by the projucer whenever I resave so I don't really want to check them into source control.
Just a guess though…Not sure how VS deals with git stuff