http://developers.de/blogs/damir_dobric/archive/2012/11/16/serialization-of-exceptions-in-workflow-manager.aspx  Note that when using workflows with Variables of type Exception, you might run into serialization issues. This is usually not a general Workflow problem. However if you use persistence feature, workflow host with enforce serialization of all variablesenCommunityServer 2008 SP1 (Build: 30619.63)