http://blogs.msdn.com/quanto/archive/2008/05/27/why-can-t-i-debug-my-vs-package-in-an-isolated-shell.aspxAaron helped me figure this out as it puzzled me for a couple of days :) It's also a topic at: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=3377742&amp;SiteID=1 If you create an isolated shell and then drop your VS packages into it, you won'ten-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/quanto/archive/2008/05/27/why-can-t-i-debug-my-vs-package-in-an-isolated-shell.aspx#8556676Wed, 28 May 2008 18:46:46 GMT91d46819-8472-40ad-a661-2c78acb4018c:8556676Visual Studio Hacks<p>My latest in a series of the weekly, or more often, summary of interesting links I come across related to Visual Studio. Scott Guthrie announced the availability of ASP.NET MVC Preview 3 . The release was also mentioned by Phil Haack and Scott Hanselman</p>