Hi, the error message (in application protocol) happens dozens of times per day and says exactly: Event 9554, Source MSExchangeIS, unable to update mailbox SD in the DS. Mailbox Guid: 77383b37-33a3-4719-b3c6-3d0545a0ccd1. Error code 0x8004010f My environment: SBS 2003 Standard SP2 with Exchange 2003. I trieb already the tool "AdFind", but it does not return a user object ("0 Objects found"). This GuiD seems to be an orphaned mail box (there are about 10 mail boxes, which are marked for deleting and are in retention period). Has someone an idea of what to find out which mail box it is? Many thanks and regards, Gil

See my post http://social.technet.microsoft.com/Forums/en-us/exchangesvradmin/thread/80db3ed9-4fbd-4e59-b51c-006a75ee5239