无法在Visual Studio 2015中使用Git Diff CSHTML文件

I am using Visual Studio 2015 with ASP .Net MVC 6 on Windows 10. As far as I can tell everything's up to date, but I haven't changed anything recently that I know of. In the last couple of days Visual Studio has stopped letting me compare the current version of an *.cshtml file to see what changes I've made. It works for every other type of file I've tried, only these ones are being a problem.I am using Visual Studio 2015 with ASP .Net MVC