I have a MSExchange 5.5 running on Windows server 2000. The MSExchangeIS service stops and this log is written into the Event Log. Source : MSExchangeIS Category : (6) Type : Error Event ID : 1188 User : N/A Description : The description for Event ID ( 1188 ) in Source ( MSExchangeIS ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: c09. Do you have any suggestion ?