I'm hoping I'm overlooking something obvious, because this is a strange problem. I have any number of Distribution Groups on our Exchange 2007 server that were upgraded/migrated from the last version of Exchange. They work well; you can add/remove users both from Outlook at the Exchange Management Console. However, any changes to the users from either of those locations don't replicate down the AD, and changes I make directly toAD don't replicate back up to Exchange. To test things out a little more, I tried creating a new security group w/ email from the Exchange Mgmt Console. When I did this, I can edit the list of users in *all 3* places (Outlook, Exchange, AD), and the changes sync properly between Exchange and AD. Anyone know what's going on here? Is it some 'pipe' that needs to be properly connected between the two servers? Thx.