After you save and restore an archived configuration through the Management Console (Configuration >General > Archive), the ProxySG appliance won't join Windows Domain automatically. The domain state remains "Joined configuration only (must rejoin)" and authentication does not work.
This occurs in SGOS 6.4.x and later with IWA Direct authentication configured (no IWA BCAAA).
This behavior is by design; it reduces security risks to Windows valid credential information.