You should synchronize all user groups if you have made a change to a user group, such as moving a user group from one AD module to another. You can also change the AD association of a user group manually, in the User Group Profile's Active Directory Associations tab.
If you have made changes to users or domain controllers, you should synchronize all AD modules. See Synchronize All AD Modules.
When you synchronize AD user groups, CC-SG retrieves the groups for the selected AD module, compares their names with the user groups in CC-SG, and identifies the matches. CC-SG will present the matches and allow you to select which groups in AD you want to associate with CC-SG. This does not update user access information in CC-SG. Synchronizing AD User Groups only maps the group names from AD to CC-SG.
A confirmation message appears when all imported user groups in the selected module have been successfully synchronized.