Had an issue with OWA 2007 recently, specifically when composing a new message. After clicking To:, instead of being the first address list displayed, the Default Global Address List was seen under the Show other address lists heading. The most recent change in the environment had been the decommissioning of the Exchange 2000 server and in this case, we did not “upgrade” the default global address list to the Exchange 2007 filtering syntax before shutting down the 2000 server. Once the address lists were upgraded, the OWA display problem was corrected.

Background Info on LDAP and OPATH

When migrating from Exchange 2000/2003 to Exchange 2007, be sure to upgrade your Email Address Policies and Address Books to new Exchange 2007 OPATH syntax filters. Previous versions of Exchange 200x used LDAP filters to build custom address lists, the GAL, email address policies, and query-based distribution groups. For example, if you created a query-based distribution group called Marketing based on the AD user property Department, Exchange 2003 would use LDAP to query Active Directory for the Department variable of all user accounts. Exchange then dynamically constructs the distribution group based on the user accounts which have Marketing specified as their Department. This provides little managment overhead but does increase the amount of resources used by the system.

Why the switch from LDAP to OPATH? I’d say its due to Exchange 2007’s use of Powershell. I have heard from multiple sources that Microsoft built Exchange 2007 as if all management tasks would be performed using Powershell, and then added the Exchange Managment Console GUI later. OPATH is likely the filtering language used by Powershell because its command syntax is easier than LDAP.

Upgrading the Email Address Policies and Address Lists

During your Exchange coexistance period, you may see a message box similar to the following when trying to view or edit the properties of an email address policy or address book:

The screenshot is hard to read but the message states “Unable to edit the specified policy. Policies created with legacy versions of Exchange must be upgraded…” This simply indicates that the syntax filter for this particular object has not been upgraded to OPATH. Please note that this does not mean these objects are not working, it simply means that in order to manage them through Exchange 2007, you need to upgrade them. The Powershell commands
Set-EmailAddressPolicy and Set-AddressLists are used to upgrade the email address policies and address books to the OPATH filtering format. Once these objects are upgraded, you will not be able to manage them in the legacy Exchange System Manager console.

For the complete syntax, connect to Upgrading Custom LDAP Filters to OPATH Filters. You can also download the following script from the Exchange 2007 Team Blog to upgrade the default email address policies and address lists to Exchange 2007 format. Save it as a .PS1 file and execute within the Exchange Management Shell.