No EditorOptionDefinition Export Found Error

Question

In Visual Studio 2013 I started getting the following error when trying to open C# files:

No EditorOptionDefinition export found for the given option name:
T         


        

Answer 1

Turning off a plugin called "Visual Assist" solved it for me.

Answer 2

Yes I had this same problem with VS2013 and WIndows 7. Renamed folder

C:\Users\YourUsername\AppData\Local\Microsoft\VisualStudio\12.0