Say you migrate from Exchange 2003 to Exchange 2007 and decommission the Exchange 2003 servers. Have you ever wondered what would happen if the Exchange 2003 Administrative Group container was deleted using ADSIEdit in an effort to “clean up” the environment?

Odds are good that the following will take place:

1. Outlook 2007 clients will be able to connect to Exchange 2007 mailboxes with no apparent problems, until you try to access a public folder. Public Folders are not accessible.

2. Outlook 2003 clients will receive the message, “Your Exchange Server administrator has blocked the version of Outlook that you are using. Contact your administrator for assistance.” Checking the Microsoft Article 924625, this error can occur for 6 different scenarios. The first being Outlook 2003 cannot access a Public Folder store.

3. If you open the Exchange Management Console and attempt view/edit the properties of the Public Folder database, you get a message indicating the PublicFolderHierarchy value contains invalid data as shown below:

The problem arises because the Folder Hierarchies msExchPublicFolderTreeContainer does not exist since the First Administrative Group container has been removed.

To recreate the Folder Hierarchies msExchPublicFolderTreeContainer:

1. Launch adsiedit.msc.

2. Expand Configuration | Configuration | Services | Microsoft Exchange | Orgname | Administrative Groups

3. Create a new container called First Administrative Group. This is assuming the name of the administrative group for Exchange 2000/2003 was First Administrative Group.

4. Right click on First Administrative Group

6. Select New Object

7. Select msExchPublicFolderTreeContainer for the class and click Next

8. Enter the following for the value: Folder Hierarchies, click Next

9. Click Finish

Create Public Folder Tree Object

10. Right click CN=Folder Hierarchies -> New Object

11. Selected msExchPFTree for the class

12. For the Value, enter Public Foldersand click Next

13. Click on the More Attributes button, select msExchPFTreeType and set the value to 1. This is very important as a value of 1 tells Exchange that this is a MAPI Tree

14. Click Ok and then finish

Populate msExchOwningPFTreeBL attribute object of the PF Stores in the Exchange 2007 organization

15. Right-click the Public Folders object just created in step 12.

16. Copy the distinguishedname value to the clipboard and then click cancel.

17. Still within ADSIEdit, expand the Exchange 2007 Administrative Group | Servers | <servername> | Information Store | Second Storage Group

18. Right-click Public Folder Database on the right-hand pane and choose Properties.

19. Locate the msExchOwningPFTree attribute and paste in the value that was copied to the clipboard in step 16. Click OK.

20. Now, wait a few moments and try to mount the Exchange 2007 Public Folder store. If the process was successful, the PF database will mount and Outlook clients will be able to login to Exchange once again.

If the Public Folder databases fails to mount within a few minutes, restart the Information Store Service and try to mount the public folder database once again.

Naturally, if you are inclined to experiment, I encourage you to perform these tasks in your lab. Should any of you repeat these steps, I’d love to hear your results!