Hi guys We have a Exc2003 org. We are migrating users from a different domain but the OAB contains incorrect entries. When taking cache mode off the correct entries display but when putting cache mode back you see some incorrect entries. I have put cache mode back on 1 machine, deleted the OAB files manually and then reopen Outlook. It then shows correct, while in cached mode, but after a while the incorrect entries display again When trying to to a rebuild of the OAB i get the error "MAPI or an unspicified service provider" ID. 00000000-0000-00000000 ID no c1050000 Have any of you seen this and know of a possible solution pls - would really help. Outlook 2003/2007 and 2010 thanks in advance

http://support.microsoft.com/kb/315250 does not work for me as i do not have a DS Server key under Exchange Provider

Hi, Please remove the old OAB file and create a new OAB file. See http://technet.microsoft.com/en-us/library/bb123470(EXCHG.65).aspx If the issue continues, maximum the Diagnostcs Logging|MSExchangeSA|OAL Generator to see what error is recorded in Application event log. Hope it is helpful. Fiona Liao TechNet Community Support

Hi Thanks for your reply Found the problem. The mailbox store on the Exchange Server that was responsible for generating the OAB was deleted. As a reult the System Attended mailbox was not available. Solve it by selecting a different Exchange Server with a mailbox store to be the generating server