Logon Failure on database “%4” – Windows account %1; mailbox %2.Error: %3 Client Machine: %5 Client Process: %6 Client ProcessId: %7 Client ApplicationId: %8

The Error event indicates that there was a logon failure to the mailbox database. This error could be seen together with event 1044. Use ERROR.exe to decode the error as it could provide information about the underlying problem. For example, the error might be MAPI_E_LOGON_FAILED or ecWrongServer or MAPI_E_NO_ACCESS. The following are some of the possible conditions for the cause of the event:

• This event could be seen during a Move Mailbox operation if a user tries to access their mailbox when it is being moved.

• The disabled Active Directory user account associated with the mailbox in question might not have the MSExchMasterAccountSID attribute populated.

• The domain controller that was first updated during the mailbox move differs from the domain controller that the Exchange Server uses during the user’s logon attempt.

• The user tries to gain access to the mailbox before Active Directory replicates the information to the domain controller.

To resolve this error, do one or more of the following:

• Do nothing. In the Move Mailbox operation, the problem will be resolved in approximately 15 minutes after a mailbox has been moved and when Active Directory replication occurs. The user will then be able to log on to their mailbox.

• Make sure that users are not accessing their mailboxes during a Move Mailbox operation.

• Make sure that the SELF account is listed in the permissions list for the Active Directory User Object associated with the mailbox in question.

• Make sure that the Active Directory user accounts are enabled.

If you are not already doing so, consider running the tools that Microsoft Exchange offers to help administrators analyze and troubleshoot their Exchange environment. These tools can help you make sure that your configuration is in line with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. Go to the Toolbox node of the Exchange Management Console to run these tools now. For more information about these tools, see Toolbox in the Exchange Server 2007 Help.