We have issues with Outlook and Exchange 2010: The global address book doesn't get updated on any Outlook clients (but works fine on the web access). We tried deleting the local address book and let the server push out the updated version, but after a local machine reboot, the global address book reverted back to the older version. We disabled Cached Exchange Mode and it seemed to fix the update issue, but we would like to keep that feature enabled.
This is a known condition for cached mode. It will always work on OWA because it always uses the online address book.
The link above has a reg entry you can put on the clients to always use the online Address Book, rather than the cached one.
Outlook 2010 downloads the OAB every 24 hours. The files are downloaded from OABVirtualDirectory and are updated every 8 hours (=Pollinterval 480). If OAB is manually updated, but not the OABVirtualDirectory, Outlook will have nothing to download.
Try this to update the OAB files:
Update-FileDistributionService -Identity Server1 -Type "OAB"