This issue will occur under the following circumstances:
The meeting presenter is adding a Microsoft PowerPoint presentation to a meeting that is hosted by Lync Server
The Lync client will stop loading the Microsoft PowerPoint presentation and provide the following error in a Lync error dialog:
<filename.pptx> can't be uploaded because it exceeds your allowable file size
The Lync Server Web Conferencing service will convert the <filename.pptx> file into several files of the BIN file type. The conversion to the BIN file type expands the size of the Microsoft PowerPoint presentation. If this expansion process exceeds the maximum value that is set for the Lync Server content storage for conferences then the upload process will fail.
Note The BIN files will be copied by the Lync Server Web Conferencing Service to the 1-WebServices-1\CollabContent folder of the Lync Server Filestore share.
The Lync Server Set-CsConferencingConfiguration PowerShell cmdlet can be used to correct issue.
Use the steps listed below to set the Lync Server content storage maximum to a higher value:
Using Server 2008 or Server 2008 R2
Click on Start, All Programs, Microsoft Lync Server 2010 or Microsoft Lync Server 2013
Choose Lync Server Management Shell
Using Server 2012
Press the Windows logo key to access the Start Page
Click on the Lync Server Management Shell tile
Enter a Lync Server PowerShell command that is similar to the example listed below: