While recently working with a customer they brought this issue to my attention. The report was that when a user shared a PowerPoint document in Lync 2013 users running Windows 8.1\IE11 failed to download the presentation. The Lync Client\LWA Stage would just sit at the “Loading” and never display the presentation. We looked at the UCCAPI logs on the client and found the error message below:

 <diagHeader>54020;reason="The WAC presentation failed with a critical error

After doing some research we found this was in fact a bug for which a hotfix was released on October 17th (http://support.microsoft.com/kb/2825686/en-us). The description stated:

Issues that this hotfix package fixes

  • Assume that Microsoft Lync 2013 is installed on a computer that is running Windows 8.1 or that has Windows Internet Explorer 11 installed. The computer is in an environment that uses an on-premises deployment of Office Web Apps Server 2013. When you try to share or view a Microsoft PowerPoint presentation in Lync 2013, the Loading indicator is displayed for longer than expected. Or, you receive the following error message:

Sorry, we ran into a problem displaying the presentation. Please try again.

If you are just discovering this issue in your environment now luckily for you we have released the Office Web Apps Server 2013 November update (2837634). This update not only contains stability and performance improvements but also contains the fix for the issue above. The update can be
downloaded via http://support.microsoft.com/kb/2837634. This should be installed similar to all Office Web Apps Server updates with
these instructions http://technet.microsoft.com/en-us/library/jj966220.aspx.

After installing this update my customer reported that it resolved their issue.