System.Runtime.InteropServices.COMException

I received a pop up error with the message System.Runtime.InteropServices.COMException. This happened when I was trying to reload a project that somehow got unloaded.

Resolution:

1. Once the solution opens, right-click on the unavailable project and select Edit project_file_name.vbproj.
2. Scroll to the bottom of the page, and delete the ProjectExtensions section.
3. Save the page.
4. Right-click again on the unavailable project, and select Reload Project.
5. Your project should now be available and you should be able to see all your project files.