I'm using Unity 5.5.4p4 with Visual Studio 15.5.1 and I'm having trouble with the problem mentionned in this thread: Problem explained here.
I have readen all of the thread, I have tried each answers (these in the comments too) and nothing works.
I have uninstalled /reinstalled VS, VS Tools for Unity, it has changed nothing. I am suspicious about the last Visual Studio Update that have introduced (again ?) this problem.