Hi `All, I am doing Gal sync between 2007 and 2010 forests. I can sync users and DL groups with new forest. But while sending mails from 2010 to 2007 DL I am getting error recipient couldn’t able to find.. Kindly advice on this. For DL we can send mails from Exchange 2010?Deena

Actually it sounds more like messaging system issue so this would be my first check. Have You checked it with messaging system administrators? Have you checked that these groups (DLs) were correctly provisioned and are recognized within Exchange as correct objects?