The SBS console has an option to create a distribution group. The link is grayed out. It is not recommended to create the group via the Exchange console.
1. Fix registry setting change:
HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ SmallBusinessServer \ Components
Add / change the DWord value “Messaging” with a value of “1”.
2. Re-run the Add Group wizard and verify works.
Let’s try this again… the issue… or rather the REAL issue if your distribution list is grayed out and this is a migrated server is that if that value is not there or “0” something happened. Review your sbssetup.log. If this is real early on in the game consider rolling back and starting over, if you’ve only now found it months later, review http://support.microsoft.com/default.aspx?scid=kb;en-us;2527626. In SBS 2008 if you see this do the registry key and the scripts in http://technet.microsoft.com/en-us/library/dd728006(WS.10).aspx
Applies to both SBS 2008 and SBS 2011