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
After a reboot and some more research I found this post from a blog. The error described is not the same error I am seeing, however, it was close enough to warrant a try.
Follow the steps:
%LocalAppData%\Microsoft\VisualStudio\12.0\
(in C:\users\'%userName%'\AppData\Local\Microsoft\VisualStudio\12.0\)Visual studio will recreate the folder and all will be well with the world (or at least VS). I love a simple solution, and I hope its of use to anybody else who runs into this issue!