"Make sure the application for the project type (.csproj) is installed."
I tried googling on this but did not find much information except that, this might happen if your project is under source control. My projects were under source control and hence I was elated as the post did carry a solution for the same (http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=8461&SiteID=1). But my elation was short-lived as the work-around didn't help me.
After breaking my head for sometime I came with a work-around that resolved the issue. Here are the steps:
- Delete the solution file and any associated source control bindings.
- Open one of the projects (open the .csproj file)
- Orcas will prompt for migration to new version. Finish it.
- Now add all the remaining projects to the newly created solution.
- Once you re-create your solution structure save it to the location from where you deleted the original one.
Also, do not forget to change the target framework to 3.5 in your project properties unless you aren't using any of 3.5 features.