Best Solutions For Offline Address Book on Workstations Not Updating Frequently Enough?

Question

We use Exchange 2010 SP2 and we set Outlook 2010 to Exchange Cached mode by default for all workstations.  This seems to work OK for the majority of email most of the time, but because we are very frequently adding and removing external mail contacts
and and adding and removing them from distribution lists, the GAL and  distribution lists memberships are frequently out of date in the middle of the work day.  
Sometimes the users can manually download an updated OAB assuming it has been updated on the server, but sometimes the OAB is not updated yet and redownloading the OAB solves nothing.  It is a lot of hassle, confusion  about bounced messages and
missing contacts and phantom names in distribution lists with this method.
I notice that for mail contacts, there is an All Contacts address book that is live, but it does not include include anything else other than contact addresses.  Distribution List memberships are still out of date until the OAB is updated on the server
and then downloaded to the Outlook client.  This is taking too long.
Is there a keyboard shortcut to force the client to do a GAL address lookup in online mode rather than using the cached OAB?
Can Outlook display both an online and offline address book for the GAL and let the user manually select online version of the GAL if a contact or new mailbox or DL has not synced to the OAB yet?
If we set the registry key to force online address books even when Outlook is in cached Exchange mode, is there any performance downside for PCs on the LAN other than the GAL being unavailable when the network is not available?
Would the Exchange server have a significantly higher load if most PCs were accessing the GAL without an OAB cache?
If we should not expect a significant increase in server load or network traffic, we might set desktops to use online access to the GAL and only laptops to use OAB.

Answer 1

Hi,
If users are accessing the GAL without OAB cache, definitely it will increase in server load and network traffic. If you are in cached mode, one suggestion is to define that in Send/Receive Settings:
Go to Send/Receive Groups -> Define Send/Receive Groups
-> Select the account and Edit -> Select
Include the selected account in this group, and check Download offline address book -> Click
OK -> Go back to Send/Receive Groups, select the frequency for automatic send/receive(Schedule an automatic send/receive every x minutes.), and then close.
I hope this setting can help in your scenario.
Regards,
Melon Chen
TechNet Community Support