The Lync 2010 client downloads a cached copy of the global address to the user’s computer. This allows users to rapidly find contacts and phone numbers. By default, it can take up to 24 hours for changes in the global address list to appear in the local copy seen by the Lync user (e.g. a phone number change). There may be times when it is advantageous to force an immediate download of the global address list.
To trigger an immediate download, two steps must be taken on the client workstation. The first step only needs to be performed once per workstation, while the second would be done each time a forced update is desired. Many times on a new install, only the first step is needed.
1) Execute the following command from the Windows Command Prompt run as an administrator (or manually add the GalDownloadInitialDelay registry key). Setting this value to 0 will force Lync to immediately download the address book instead of randomly selecting a time to check the server.
reg add HKLM\Software\Policies\Microsoft\Communicator /v GalDownloadInitialDelay /t REG_DWORD /d 0 /f
2) Exit the Lync client and manually delete the GalContacts.db and GalContacts.db.idx files from the user’s profile directory. If the .db file still exists during startup of the client then Lync may still wait for that random interval between 0 and 60 minutes before checking for changes on the server’s address book files. By deleting the file the Lync client must download an entire new copy, forcing it to pick up any changes.
On Windows XP workstations:
%userprofile%\Local Settings\Application Data\Microsoft\Communicator\sip_<username@domain>\
On Windows Vista or Windows 7 workstations:
Restart the Lync client and search for any of the recently changed information, for example the Telephone Number added to this Active Directory user account now appears for the Lync contact. You may have to wait a couple of minutes while the address gets built.