Lync Address Book


I’m sure a number of you had this problem too, a user complain that when he/she search the Lync client or phone address book for a user, they get no results.

First I would like to explain briefly how Lync Address Book is generated and synchronized.

  1. Changes done to the User account in the Active Directory are synched automatically with Lync every 60 sec.
  2. Those changes are written to the SQL back-end of your Lync Deployment.
  3. Every 24h (1:30AM server local time) Lync Address book server will start synchronization job that pull recent data stored in the SQL rtc database, and write them to the Address Book files.
  4. Lync Client or Lync Phone Edition download any updated address book files (.dabs & .lsabs) and update the “GALContact.db” saved locally, this process happen randomly by the Lync Client or Phone Edition.

Understand your Address Book Configuration

You can use the PowerShell to get the Configurations of your Address book server:


Things to do – Server side

Update user database

If for some reason normal replication of the changes in Active Directory didn’t take place, you can always start it manually using the PowerShell

Command line:


Note: this command line will remove and the entire copy of the Active Directory information in the SQL database’s address book, and regenerate a totally completely new copy – this should not be necessary under normal circumstances.

Update Address Book

You can use PowerShell command line to synchronize Active Directory data in the SQL database into address book files in the shared folder of the Lync.


You can check the Lync Event logs for events with source “Lync address book Server” and Event ID:

  • 21005
  • 21010
  • 21056

Those should show you the starting of the Synchronization, the summary of the synchronizations and how much data been copied, and the final result of the Synchronization.

Things to do on the Client Side

Usually when starting the Lync client it takes between 1 minute to 60 minutes for the client to download the new changes and apply it to the GAL db files, to force the changes do the following:

  1. Close the Lync client
  2. Under windows 7 & 8, go to %userprofile%\appdata\local\microsoft\communicator\sip_<username@yourdomain>
  3. Locate and delete the GalContacts.db and GalContacts.db.idx files.
  4. Restart the Lync Client, it will force the Lync Client to download a new copy of the GAL db files.


Those steps should be enough to fix your problem with the Client Address Book search queries.

Author: Lyncdude

A Senior Service Engineer with more than 9 years of experience in Microsoft Exchange and Microsoft Lync Server / Skype for Business. Egyptian guy lives and works in Frankfurt - Germany. what is written in this blog is my own opinion and thoughts, not my employer and does not reflect their opinion

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