POWER SHELL
Update-OfflineAddressbook “Default Offline Address List”
Update-FileDistributionService
CONSOLE
Go to the Exchange management console, under "Organization Configuration" select the "Mailbox" container, go to the "Offline Address Book" container and right-click update on the address book you want to generate.
You can monitor the status of the generation of the OAB by looking at the time stamps of the files in <Exchange install directory>\V14\ExchangeOAB\<GUID of the Address Book>
Once the address book has been generated, you can speed up its distribution by forcing an update of the distribution file service, using Update-FileDistributionService.