I updated a Community Server 2.1 site SDK to SP2 the other day and when firing up the debugger in Visual Studio 2005 I received the following message, "Unable to start debugging on the web server. The debug request could not be processed by the server due to invalid syntax."
Microsoft has a good MSDN article on this with one of the things to check is to run the app in Visual Studio without debugging using "Start without Debugging." When I did I realized the url was http://localhost/cs. This is CS's default project url, but not of the site I just upgraded to the SP2. My site's url was http://cs21demo.
I'll get straight to the fix. The SDK's web .CSPROJ file's IISUrl default setting is http://localhost/cs. To change this setting and debug your Community Server Web Application you'll need to update the Web Application's Startup Project Url with Properties->Web tab as shown below. Once that is done, you can press F5 and step through the inner beauty of Community Server at your leisure.
