This particular bug has frustrated me for quite some time with ASP.NET 5 projects in Visual Studio 2015:
“An error occurred trying to load the project properties window. Close the window and try again. COM object that has been separated from its underlying RCW cannot be used.”
I ran into it very early on around BETA 2 I believe. I messed around with a number of different settings trying to see the cause. Didn’t find anything, at last time I checked very early last year, I couldn’t find anything on a “Good ol Google Search”. Recently, I have now had to address the issue more seriously as we begin considering ASP.NET 5 development for production scenarios.
It turns out this little bug is related to a VS Extension for Commenting called GhostDoc:
I’m very happy to confirm that a simple upgrade to at least GhostDoc 5.0+ appears to resolve the issue.
If your married to something before 5.0, I think there are some nightly builds that have this fixed in 4.x, check out the issue thread: