I recently installed Visio Viewer 2016 for a user who needs to be able to look at Visio files but does not need to edit, just gather information. After a reboot, when he attempts to open a .vsd or .vsdx file from an email he gets the error " The Microsoft Visio Viewer was not able to complete the operation." It is attempting to open in IE with the Visio tool bar as expected. I tried saving the files locally and opening from his computer and get the exact same error. I found a post that suggested changing the activex controls to allow for prompts to allow activex and it is still not working.