VS 2015 - Tools for Unity - Attach to Unity doesn't work anymore

After a few months not working with Unity i am not able to attach the VS debugger to Unity anymore. For that reason i updated VS 2015 with Update 3 and installed the latest VS Tools for Unity.

Still it’s not possible to attach the VS debugger to Unity. No errors, the “attach to unity”-button just goes grey for a short moment and then becomes pressable again, while certainly nothing stops at any breakpoints.

Used software:

  • VS 2015, Update 3
  • Unity 5.5.0f3 Personal
  • Visual Studio Tools for Unity 2.8.0.0 (that’s what it tells in Unities Help->About Dialog, as well as in VS 2015 Extensions and Updates)

Any help is much appreciated!

Found the solution for my specific problem: My firewall was blocking “Microsoft Visual Studio 2015 Universal Windows App Development Tools”