An interesting co-existence problem came up yesterday. It appears that there is a known issue with the Lync 2010 client and Windows 8, where it is possible to fire off multiple instances of communicator.exe, which then causes the Lync 2010 client not to even launch.
Well, the Lync 2013 client has some new coding that prevents multiple instances from starting. Now, this is a bit interesting because, in the past, OCS/Lync clients have never been backwards compatible. In case of Lync 2013, it does work with Lync 2010. Until… you add in Group Chat 2010 in the mix.
The Lync 2013 client will, as a single client, work with Lync Server 2013 and Persistent Chat. One of the nice selling points is that running 2013 means reducing the need for a separate chat client.
Well, the thought was, why not deploy Lync 2013 to connect to Lync Server 2010, and continue using the Group Chat 2010 client to connect to the Group Chat server? Well, the answer is that the Group Chat 2010 client doesn’t recognize that the Lync 2013 client is running and this causes the Group Chat 2010 client to not only display all rooms, but also display all contacts as shown here. Yes, I had to hack this one up to protect the innocent.
Anyway, as you can see from the image, it is possible to send/receive IMs in the Group Chat 2010 client, even though the Lync 2013 client is also running. What is the answer? I have no idea…