Tonight, I ran into a scenario where adding the SqlTrackingService to my WorkflowRuntime set of services caused the completion of a simple workflow to hang. To diagnose, I instructed Visual Studio to break when exceptions were thrown. With this, I was treated to a break in System.Data.Sql.SqlConnection.OnError. The SqlException being thrown stated “MSDTC on server ‘[machine name]‘ is unavailable.” If you look, you’ll see that MSDTC is a manual start service on Vista. To fix this issue, just start MSDTC in the Services Control Panel applet and run your workflow code again. You’ll be treated to full tracing at this point.