If you receive this error:
The Lync 2010 client or the Office Communicator client does not download the corporate address book and displays a notification: "Cannot Synchronize Address Book"
Give the following a shot:
- Shutdown the Lync client
- Force the Lync client to download the address book immediately the next time it starts:
- Open the registry to HKLM\Software\Policies\Microsoft\Communicator
- Modify (or Create) the DWORD the registry key “GalDownloadInitialDelay” and set it to 0 (that is a zero)
- This can also be done from the command line:
- reg add HKLM\Software\Policies\Microsoft\Communicator /v GalDownloadInitialDelay /t REG_DWORD /d 0 /f
- Delete the Existing Local Address Book Files:
- On Windows 7 or Vista machines, open Windows Explorer to the directory:
- %userprofile%\AppData\Local\Microsoft\Communicator\sip_user@example_domain
- Delete the files GalContacts.db and GalContacts.db.idx
- On Windows 7 or Vista machines, open Windows Explorer to the directory:
- Restart the Lync client.
• The address book should be available in less than an hour.
I found the solution here: http://blog.insidelync.com/2012/02/lync-address-book-client-synchronization-errors-and-common-problems/ Give it a read, it's very thorough.