EntryType : Error
EventID : 9334
Message : OALGen encountered error ffffffff while initializing the offline address list
generation process. No offline address lists have been generated.
Please check the event log for more information.
- Default Offline Address Book

Category : OAL Generator
CategoryNumber : 13
ReplacementStrings : {ffffffff, Default Offline Address Book}
Source : MSExchangeSA
TimeGenerated : 7/17/2008 3:10:31 PM
TimeWritten : 7/17/2008 3:10:31 PM

EntryType : Warning
EventID : 9109
Message : OALGen encountered an error ffffffff (internal ID 505068d) while generating address list ‘/o={Organization Name}/cn=addrlists/cn=oabs/cn=Default Offline Address Book’. Check other logged events to see if this is a serious error.
- Default Offline Address Book

Category : OAL Generator
CategoryNumber : 13
ReplacementStrings : {ffffffff, 505068d, /o={Organization Name}/cn=addrlists/cn=oabs/cn=Default Offline Address Book, Default Offline Address Book}
Source : MSExchangeSA
TimeGenerated : 7/17/2008 3:10:31 PM
TimeWritten : 7/17/2008 3:10:31 PM

Microsoft told us that this is a Bug and they are working to solve it, but don’t worry there is a workaround to generate the Offline Address Book.

When we are installing the mailbox server role the setup process will create the following registry value ‘SYSTEM\CurrentControlSet\Services\MSExchangeSA\Parameters\{Clustered-Mailbox-Server name}\OabDropFolderLocation’ which is the shared registry location between the server nodes, and points to the existing path on shared storage.

The bug is that the Exchange 2007 can not generate the OAB on the shared media using this type of cluster. So you have to change the registry value to point to a path that is stored locally on the node, e.g. ‘C:\ExchangeOAB’.
Now try to generate the offline address book.
Update-OfflineAddressBook “Default Offline Address Book”
The OAB must now be successfully generated. Do the same procedure on the other node.