I asked myself the very same question and found the answer here: http://sharepointsolutions.com/sharepoint-help/blog/2011/07/what-replaced-the-build-dynamic-string-workflow-activity-in-sharepoint-designer-2010/ Extract Substring from Index of String If you change the starting character from 0 to 1 , this activity will work exactly like the Build Dynamic String activity did in SharePoint Designer 2007. Thanks to http://sharepointsolutions.com/sharepoint-help/members/rickyspears/.