Lenovo Video Issues with Communicator – Lync & OCS 2007 R2


Lately I have been asked about Video issues in Lync and R2 Communicator – Communicator freezes once you accept inbound video call.
I did search the net, and came across the following article written by Chad McGreanor – thanks 🙂

This issue are related to the nVidia display driver with Lenovo T420s, T520 & W520.

Lenovo has been working on updating their site with the current Nvidia drivers, but as far as I know – It’s not updated yet !
Go to Nvidia directly and download the current driver that solves this issue.
Link: http://www.nvidia.com/Download/index.aspx?lang=en-us

After upgrading nVidia drivers, everything works 🙂


Communicator/Lync issues with “Fast User Switching” on Windows 7

During work on OCS 2007 R2 and Lync projects, I have come across some strange behavior on Communicator and Lync, this behavior has only been noticed with computers accessed by more than one person – Often “Common Area PC”

When a user is logged on to a computer and has locked the computer and a new users logs into the same computer by using “Switch User” functionality, the new user are having problems using Communicator/Lync for any type of Audio calls.

If the user try to do a PSTN call there is a constant dial tone in the background and the call will eventually terminate.
If the user try to join a A/V Conference, there is no audio and the conference call will end.

Microsoft has confirmed – in mail – that there is an issue with FUS (Fast User Switching) and Communicator/Lync.
They have also done some investigation on this, but the change has been consider to large for the current available clients.

Work Around:
Since this problem/issue mostly occurs at “Common Area PC”, often meeting room pc, there is possible to turn off FUS on those computers. This can be done in GPO.

Another workaround would be to create a trigger that trigger’s on “Computer Lock” and terminates the Communicator process. The same trigger will trigger’s on “Computer Unlock” and restart the Communicator process.
This is probably NOT the best approach, but it will “solve” the problem.

Multiple IP addresses on Windows 2008 R2 – What’s the primary/default address?

Lately I have been working and troubleshooting some OCS Edge installation, where the Edge server didn’t have internet access. Internet access is required for OCS Edge, to check certificate revoke lists and so on.


You assign several ip addresses to a network adapter on Windows 2008 R2. You use only the primary ip address for outgoing traffic. Firewall only allows internet connection from the primary address, traffic coming from other ip addresses is blocked by the firewall.


How does Windows selects what address to be used for outgoing traffic?
It normally selects the lowest of addresses, but this is not 100 % consequent.

How do you define on of the IP’s as Primary?
You can’t by default.


Microsoft have released a non-official hotfix that solves this problem – KB article 2386184.
This hotfix add a new flag to the NETSH command. This new flag is SkipAsSource.

I have NOT included the hotfix with this mail, as I think that if Microsoft is checking the request for this hotfix.
Maybe they make it public, if the requests increases.

What does this do:

This new flag tells the operating system to NOT use the ip address as a source address for outgoing traffic.


netsh interface ipv4 add address “Interface Name” “IP Address” “Net Mask” SkipAsSource=true

This command adds an additional ipv4 address to the interface.
To list the IPv4 addresses that have SkipAsSource flag set to true, run the following command:

netsh interface ipv4 show ipaddresses level=verbose

I hope that this will help some of the OCS Edge installations out there, that have restrictions on internet access.

A BIG thanks to Bjørnar Selvén in Atea, for helping out with crucial information.