In that case the whole OAB is being downloaded again.
I might have a problem with my Offline Address Book in Outlook.
If you don’t see the xml data check the install location if the xml exists i.e: C:\Program Files\Microsoft\Exchange Server\V14\Client Access\OABcf12789-0f60-4c83-9f24-c42637ca00e8\If exists, try server localhost in Explorer i.e: https://glob-srv-cas3uk/OAB/7cf12789-0f60-4c83-9f24-c42637ca00e8/If you get Error message when you visit a Web site that is hosted on IIS 7.0: “HTTP Error 500.19 – Internal Server Error” then check the KB942055 ( for error code and resolution.I assigned only Read rights (that is, I removed Read & execute): Once I okayed that new permission, Outlook was immediately able to download the Offline Address Book. Oh, and trying to browse directly to the OAB URL now fails with a 403 – Forbidden message: Fortunately it seems that Outlook knows how to provide credentials and get what it needs.l’m always a little nervous to follow the recommendation of some web site that tells me to add permissions.The 500 error led me to this article which recommends changing the permissions on the web.config file in the OAB directory. Here are the simplified instructions that worked for me: 1. Navigate to Server SBS Web Applications, then the OAB virtual directory. In my case, I saw only SYSTEM, the SBS admin user, and the Administrators group listed.We want to add Authenticated Users, so click on Edit and and then Add and put the Authenticated Users in there.