Mail attribute not updating when using ESM

When using the ESM (Exchange Management Console) on Exchange 2007 to manage email addresses without a E-Mail address policy (i.e. custom addresses) the mail attribute of the user isn't updated (as seen on the General tab in ADUC).

To update the mail attribute of the user you must start ADUC (Active Directory Users and Computers) and modify the attribute to be equal to the primary SMTP address. If you don't do this you can have errors (EventID: 9327/OAL Generator) with the Offline Address Book (OAB) generation and users will be missing in the GAL/AL for Outlook users in cached mode.

You will also get information about which recipients missing in the Application log of the server building OAB's if you have Medium or higher diagnostic level on the OAL generator.

Set diagnostic level on OAL generator

Set-EventLogLevel -Identity "MSExchangeSA\OAL Generator" -Level Medium

After running a new update of the OAB you will find information like this in the Application log:

Event Type: ErrorEvent

Source: MSExchangeSAEvent

Category: OAL Generator

Event ID: 9325

Description:OALGen will skip user entry 'username' in address list '\Global Address List' because the SMTP address '' is invalid. - Default Offline Address Book

Summary

Use E-mail policies as much as possible when creating e-mail addresses for the users. If this isn't possible then you must remember to manually enter the mail attribute field in ADUC for the user until Microsoft releases a patch for this error.