Hi, I have an Exchange 2010 install with legacy Exchange 2003 servers still in use. Users that are moved to Exchange 2010 from 2003 are experiencing issues when in cached mode, The offline address book will not download correctly to Outlook (2007) and in the process of trying to retrieve it, Outlook endlessly asks for user authentication. Authentication is supplied but it just asks again after a couple of seconds. When cached mode is switched off then this is not an issue. Checking on the mailbox server and it is getting Errors 9334 OALGen encountered error 80004005 while initializing the offline address list generation process. No offline address lists have been generated. Please check the event log for more information. 9330 OALGen encountered error 80004005 (internal ID 50007a1) accessing Active Directory 9334 - The error in 9334 mentions could not find the address list with Guid... The Guid listed in error 9330 and 9334 is different from the Guid listed on the Exchange 2010 c:\program files\microsoft\exchange\v14\ExchangeOAB. I am presuming this is looking to an old version of OAB that is listed in AD but how do I get rid of this and force the Exchange 2010 OAB to generate? Thanks B

Hi, For this issue, please refer to the below article to fix this issue: Exchange 2007 Offline Address Book (OAB) keeps asking for authentication http://bradmarsh.net/index.php/2009/03/03/exchange-2007-offline-address-book-oab-keeps-asking-for-authentication/ Thanks Allen