I'm building an orchard CMS site. Initially, I downloaded the zipped version, but VS complained of the error: "Object reference not set to an instance of an object" in project Markdown.csproj, line 1. This made no sense to me, so I tried installing it from Web Platform installer. That worked great for a while. Then I restarted visual studio after some theme changes and got the original error again. I've attempted to revert the theme changes and tried relaunching VS in admin mode. Still no dice.
I can find absolutely nothing on the subject of Markdown.csproj via google. If anyone has suggestions I'm all ears. Thanks.
In case anyone else runs into this, the solution for me was to migrate to orchard 1.4 via the source instead of web platform installer.