[Microsoft] Contribution for Support Knowledge Base
The most popular post on this blog with over 50k views is Error while trying to run project: Unable to start debugging on the web server. Just recently I turned on comments again (since it has caught some spam over the years) and found a valuable suggestion from Michael:
gracias mucho - Microsoft doesn't seem to know this - or refusing to put it in their help document
Microsoft please update KB (306165) PRB: "Unable to start debugging on the Web server" error message when you debug ASP.NET applications with this information.