This article has been archived. It is offered "as is" and will no longer be updated.
Important note The update that this article previously described has been removed from Windows Update. If you install the update, you may recieve an error message when you take any of the following actions:
You try to uninstall Office Communications Server 2007.
You upgrade from the evaluation version of Office Communications Server to the full version.
The error message that you receive resembles the following error message:
Microsoft Office Communications Server 2007 installation or uninstallation requires that VC++ 2005 SP1 Redistributable is already installed. Either use Setup.exe for installation or run VCRedist_x86.exe included with the product to install the redistributable.
Note This update has now been replaced by update 953907. Update 953907 contains all the fixes that are listed in this article. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
953907 Description of the update package for Communications Server 2007: June 2008
To work around this problem, open the Add or Remove Programs item in Control Panel, and then remove the "Update for Office Communications Server 2007 (KB 949260)" update.
Note The authentication protocol that is used by Communications Server and its clients has been updated to require a signature in all messages. This includes the first message that carries the challenge response. The version number of the protocol that is advertised in the challenge response has increased to version 4. Challenge responses that use version 4 of the protocol must contain a signature. The signature is a digest of the identifying headers in the message that is calculated by using the session key. To make the Conferencing Add-in for Microsoft Office Outlook work correctly, this update for the Conferencing Add-in must be installed. Additionally, to make sure that all other clients work effectively against this update, the following hotfixes must be installed on the clients:
948738 Description of the update for the Conferencing Add-in for Outlook: April 11, 2008
946764 Description of the Windows-based Live Meeting 2007 client update package: April 11, 2008
946164 Description of the update for Communicator 2007: April 2, 2008
If the server is updated with these hotfixes, but the update for the Conferencing Add-in is not installed, you may receive the following error message when you try to schedule a meeting by using the Add-in:
Cannot connect to server because the information in the User Accounts dialog might be incorrect or improperly formatted. Please verify that this information is correct, and then click Test Connection. If you still can’t connect, then the server might not be available.
The Unified Communications Client API Software Development Kit (SDK) also has been released, and it includes the fix for this issue.For more information, click the following article number to view the article in the Microsoft Knowledge Base:
950559 Description of the update for the Unified Communications Client API SDK
The hotfix that is described in this Microsoft Knowledge Base article also contains the fix for this issue:
949259 Error message when you send an instance message to a contact that is hosted on Communications Server 2007 in Communicator 2005 or in Communicator 2007: "This message was not delivered"