Office Web Apps Server in the Lync Server 2013 Preview

July 2013 Update: This article was originally written for the Preview release of Lync Server 2013.  I have since updated it for the RTM version and added a couple of more tips.

What Is The Office Web Apps Server?

The Office Web Apps Server is the next incarnation of the Microsoft Web Access Companion Server (WAC) which basically allows applications such as Lync and SharePoint to stream PowerPoint presentations efficiently to a variety of end-points in higher resolution.  Lync Server 2013 Preview leverages the Office Web App server to broadcast PowerPoint presentations to the Lync 2013 clients – including the Lync Web App – in a Lync Online Meeting (conference).

Admittedly I question the wisdom of introducing another server piece to Lync that cannot be collocated on the Lync server (and of introducing another component with the acronym “OWA”!).  Do remember that all of what we see today is a Preview build. I suspect if will still be necessary when Lync Server 2013 ships but I am not sure either.

Regardless, the big carrot is enhanced PowerPoint presentation viewing in Lync Conferences – specifically on higher-resolution displays and a wider range of mobile devices which greatly enhances the collaboration experience.

An Office Web Apps Server is Required when you Install a Lync Sever 2013 Preview Pool

The New Front End Pool Wizard in the Lync Topology Builder requires you to specify an Office Web Apps Server.  However, you can specify one in Topology Builder without one being fully deployed yet as shown below:


You will get an frequent Event Log Error #41033 from the LS Data MCU if the Office Web App server is not available as shown below:


The error message is initially deceiving because it references a certificate problem, but in this case the Office Web Apps are just not deployed to the Office Web Apps server we specified in the Topology Builder for this Front End pool.

The User Experience when Office Web Apps Server is Not Available (Deployed and Configured)

Without an Office Web Apps server available, Lync 2013 Preview users homed on the pool will see the following when they try to share a PowerPoint presentation in a Lync conference:


Tips for Installing the Office Web Apps Server

Install Note #1: The first important thing you need to know is that you cannot collocate the Office Web Apps Server on a Lync server, or any other server (including an Exchange, SharePoint or SQL server). The Lync Topology Builder is smart enough to not allow a new Office Web Apps Server to be defined with an FQDN that is in use anywhere else in the topology:

> Fully qualified domain name (FQDN) <server FQDN> is already in use in this Topology.

Install Note #2: Fellow Lync MVP Tim Harrington has a good blog post on Installing Office Web Apps Server for Lync Server 2013. Just follow his steps. I include some additional helpful information below to get your Office Web Apps installation up and running.

All of the TechNet documentation on the Office Web Apps Server Preview is here: Deploy the infrastructure: Office Web Apps Server Preview.  This has all the information you need about deploying, planning and configuring.

Install Tip #3: The Office Web Apps Preview installation package currently downloads as an .img file (WebAppsServer_en-us_x64.img).  This is a bit of a hassle because you need to unpack it to get at the actual setup files. You need a separate utility to get at the contents of the .img file.  You can use Microsoft’s Virtual CD-ROM Control Panel v2.0.1.1 (if you can find an official Microsoft link to it – I couldn’t) or my preference MagicISO Virtual CD/DVD-ROM (it saves you from having to install the .sys driver and is more user friendly).

Install Note #4: The Office Web Apps Farm used by Lync Server 2013 needs …. what else … a certificate.  For internal uses (the Internal URL) this can be a certificate issued by your internal CA. You specify the Friendly Name of the certificate on the New-OfficeWebAppsFarm cmdlet to create the Office Web Apps Farm.

If you are like me, your immediate thought will be to use the AD Certificate Web Site on your CA (i.e. http://<FQDN of your CA>/certsrv) in a browser on the Office Web Apps server to request a certificate as follows:


However, if you have a default Windows 2008 R2 Enterprise Certificate Authority (CA) install, you will likely receive this nice error after you try to submit a request through the web site:

> “Web site for the CA must be configure to use HTTPS authentication”

Thankfully Terence Luk has an excellent post on using the IIS Management tool to create a certificate request in a text file, use the AD Certificate Web Site on your CA to issue the certificate, and then assign it using the IIS Management tool again.  You can find his blog post here:

Additional reminders for generating and assigning the Office Web Apps certificate:

  • In your certificate request, don’t forget to select “Web Server” as the certificate template.
  • You need to be focused on the server in the IIS management console to have the “Server Certificates” selection available.
  • Don’t forget to save your certificate as a Base 64 Encoded PKCS #7 file – this is NOT the default option.

Finally, here is the what a sample successful internal deployment of the Office Web App Farm looks like:


Install Note #5: if you are installing on Windows Server 2012 and getting errors when you try to run WAC make sure you have the following Windows features installed.

  • NET-Framework-Features
  • NET-Framework-Core
  • NET-HTTP-Activation
  • NET-Non-HTTP-Activ
  • NET-WCF-HTTP-Activation45

Install Note #6: check the installation drive if you receive a “response message does not match the content type of the binding” error on Windows Server 2013

Fellow MVP Ken Lasko details an error when installing Office Web App Server 2013 on anything other than the standard C drive (i.e. C:\Program Files\Microsoft Office Web Apps on Windows Server 2012).

See “Errors After Installing Office Web App Server on Non-Standard Drive“ by Ken Lasko.

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