To search the GAL, choose one of the following options: After clicking People (Outlook 2016) or Contacts (Outlook 2011), enter your search term in the 'Find a Contact' search field.In the Offline Address Book dialog box, make sure that the Download changes since last Send/Receive check box is checked then click OK.
In the Tools menu, point to Send/Receive, and then click Download Address Book. Please visit the document on How to turn on or off Cached Exchange Mode for ( and ). Note: In order for some GAL entries to show up properly you may need to turn off Cached Exchange Mode. Updating your address book synchronizes the cached Address Book with the Global address book, and may fix instances of mail that is bounced back to the sender. When this happens you may be missing new entries, see non-existent entries, or notice incorrect entries. When changes occur within the main (Global Address Book) on the Exchange server computers running Outlook 20 may not automatically receive the updates.