I recently upgraded to SQL 2014 from SQL 2008 R2 and my SSIS packages created from 2008 no longer work. I traced the issue to a Script Task referencing a namespace in the assembly "microsoft.sqlserver.manageddts". I tried going to Projects > Add Reference to select it but still get a "not found" error. The file path for this assembly under the list of references correctly shows were it exists on my PC, so I'm not sure why it can't find it. I also recently installed the latest .Net version, but I'm not certain if this could also be the cause. Any ideas?