At a customer site I got EventID 12330 LS Server stating that abserver worker process failed to initialize itself. A quick google search lead me to this forum article:http://social.technet.microsoft.com/Forums/en-US/ocsaddressbook/thread/6365091e-ec34-46cc-b9f7-e362b9084bb3

There MVP colleague Johan Veldhuis found a cause of this problem. The cause was that the SQL database being backed up when the Addressbook was being generated resulting in low responce time and therefore the process did not complete its update. The addressbook is being generated at 01.30 default every night, and if it can not update we will see this kind of behaviour

Resolution

• Use the Set-CsAddressBookConfiguration cmdlet to change the generation time
• Set-CsAddressBookConfiguration -RunTimeOfDay 23:00
• This will set the addressbook update to happen at 11 in the night to ensure no SQL backup overlap

Detailed error messages

Event ID 12330    LS Server

Failed starting a worker process.

Process: ‘C:\Program Files\Microsoft Lync Server 2010\Server\Core\ABServer.exe’  Exit Code: C3E8302D!_HRX! (The worker process failed to initialize itself in the maximum allowable time.!_HRM!).
Cause: This could happen due to low resource conditions or insufficient privileges.
Resolution:
Try restarting the server. If the problem persists contact Product Support Services.

Event ID 12331

Worker process exited prematurely.  The process will be automatically restarted.

Process: ‘C:\Program Files\Microsoft Lync Server 2010\Server\Core\ABServer.exe’  Exit Code: 0!_HRX! (The operation completed successfully.
!_HRM!)