Mac OS X Terminal Services Client installation
Please use the Microsoft Remote Desktop Client for Mac from iTunes store (version > 8.0, red icon).
Don't use the previous version which is a part of Microsoft Office software package (green/blue icon). It's deprecated and is not developed any more.
More information about the product can be found at: https://itunes.apple.com/en/app/microsoft-remote-desktop/id715768417?mt=12