The type or namespace name 'Name' could not be found (are you missing a using directive or an assembly reference?)
If you migrate custom workflow activities from SharePoint 2010 to SharePoint 2013 you may receive error in ULS while attempting to run the workflow: Microsoft.SharePoint.SPException: <Error><CompilerError ... Text="The type or namespace name '<Name>' could not be found (are you missing a using directive or an assembly reference?)" /></Error>. Also similar error is displayed in SharePoint Designer in place of the activity.
I found the solution in this great article . To resolve the issue you should move the <authorizedType> node to
in the web.config of the SP 2013 web app.