When editing a Workflow in SPD 2013, the WF forces the WF to open in visual mode and I am unable to publish or change  the view without crashing SPD.  When any action is taken on this workflow a progress bar flashes and "Exporting Workflow" is displayed --  this process either crashes SPD or locks the computer. 

I have completed the following without success:

uninstalled & reinstalled SPD and Visio (32 bit),

cleared caches, 

uninstalled and reinstalled SPD and Visio to 64 bit,

installed all updates

Any guidance is much appreciated.