Cannot add local interpreter

I have a virtual environment on my desktop that I would like to register as an interpreter.  When I use the "Add Local" option in Preferences -> Project Interpreter, I am able to select the the location of python executable in the virtual environment.  However when I press ok nothing happens.  The dialogue box closes but the interpreter has not been added to the interpreter options. My default interpreter is selected instead.

It is also not in the list when choosing "show all".  In the "show all" box I am able to manually add the interpreter  by "editing" an old interpreter on the list.  After clicking ok on the "show all" box by desired virtual env interpreter is selected in Preferences -> Project Interpreter.  It displays all the correct packages and the correct path to the interpreter.  But when I click 'ok' or 'apply' nothing happens.  The glow around the 'ok' or 'apply' box will move but nothing else happens.  The preferences window will not close.  PyCharm is not frozen as I can select 'Cancel'.

I am on macOS Sierra with the latest public updates and am using PyCharm Professional (should be the most updated as I downloaded and installed it yesterday).  In the past, I have used a virtual env interpreter with the Community Edition with no problems.