I am sure you must be facing this issue suddenly in your OCS production environment. This is quite interesting. Microsoft releases ‘Security updates’ and ends up bringing down a production server. One of the Windows security update KB974571 has broken OCS R2; that’s why OCS Front-End service Stopped.
You will receive a service specific error 3286842403 (0xC3E93C23).
Log Name: System
Source: Service Control Manager
Date: 10/15/2009 11:22:54 AM
Event ID: 7024
Task Category: None
The Office Communications Server Front-End service terminated with service-specific error 3286842403 (0xC3E93C23).
Office Communications Server Front-End
Cause: Windows security update KB974571 has broken OCS R2; that’s why OCS Front-End service Stopped.
Resolution: Remove this Windows update & restart the OCS Front End Service.
It’s a bug in windows update….. They have managed bring down a critical product service with the release of a windows update.
This could happen for LCS & OCS R1 deployments also.
Please also note of another complexity that affects end users –
Auto-upgrades are enabled on end user desktops as well. Security Update KB974571 will be applied on end user desktops. Hence users will not be able to login to OCS though the FE Server is up, after removing the offending update from the FE Server.
But the users without this Security update will be able to login to OCS. To address this issue, end users too need to uninstall this update from their desktops. This is applicable for LCS as well.
Take a look at Communicationsserverteam.com for more info