We have a Samba 3.0 PDC and and Exchange 5.5 mail server, when we try to upgrade the exchange server to SP4 a Dr. Watson error pops up Dr. Watson Application exception occurred: App: exe\exupdate.dbg (pid=366) When: 11/10/2003 @ 10:17:16.218 Exception number: c0000005 (access violation) The error does not occur on a native NT 4 domain, and poses no problem on a Exchange server which has been upgraded on an NT4 domain and then transfered to a Samba PDC. Any suggestions would be greatly appreciated. Thanks