Get communicator chat logs from Achieving server
Previously OCS administrators were not confident enough to get Old chat logs because it requires more complex SQL queries to get chat logs exported from OCS Achieving server .Now MS released a new tool "OCSArchiveViewerSetup" which is having a GUI to retrieve the chat logs easily.
In the achieving and monitoring server install OCS Achieving tool "OCSArchiveViewerSetup". This is a free tool and the installation doesn’t cause any service interruption (as I experienced) .It can be downloaded from microsoft (just google it )..After installation it will ask for database to locate .Add the server name and instance name (ServerName/Instance) if default installation no need to specify instance name, and click Connect.
Put the complete sip Uri of the user to get the chat log. There is an option to select the time limit to get more refined chat logs .The tool is having an option to export the chat logs to IE too.