We had a hardware failure on our SBS 2003 box corrupting the Exchange database log files. I repaired the information stores and have restored the server back to full operation. There are not remaining obvious data corruptions. I am receiving intermittent NDR's from exchange clients to both internal and external recipients.Your message did not reach some or all of the intended recipients.Subject: RE: ********Sent: 18/05/2009 6:15 PMThe following recipient(s) could not be reached:'*Contact Name*' on 18/05/2009 6:15 PMThe e-mail address could not be found. Perhaps the recipient moved to a different e-mail organization, or there was a mistake in the address. Check the address and try again.<domain_name.***.** #5.1.0>I have also turned the categorizer logging level up to level 7 and am receiving the following errors in the Event viewer, which seem to be corresponding to the time that the bounce backs are received.Event Type: ErrorEvent Source: MSExchangeTransportEvent Category: Categorizer Event ID: 6007Date: 19/05/2009Time: 9:47:29 AMUser: N/AComputer: SERVER_NAMEDescription:Categorizer encountered a hard error while processing a message. The function 'CICategorizerMailMsgsIMP::HrPrepareForCompletion' called 'pIE->pIMailMsgProperties->Commit' which returned error code '0x80040158' (). ( f:\tisp2\transmt\src\phatq\cat\src\icatmailmsgs.cpp@971 )Event Type: ErrorEvent Source: MSExchangeTransportEvent Category: Categorizer Event ID: 6007Date: 19/05/2009Time: 9:47:29 AMUser: N/AComputer: SERVER_NAMEDescription:Categorizer encountered a hard error while processing a message. The function 'CICategorizerListResolve::CompelteMessageCategorization' called 'm_CICategorizermailMsgs.HrPrepareForCompletion' which returned error code '0x80040158' (). ( f:\tisp2\transmt\src\phatq\cat\src\icatlistresolve.cpp@363 )Does anyone know where to start looking to repair this problem.

Hi,From the error event ID, I suggest we run Isinteg and offline defrag on the database to ensure the the database is health.Example: Eseutil /d database_file_name Isinteg -s server name -fix -test alltests After that, please check this issue.