Can't share a PPT in Skype for Business 2016 when blocking legacy PowerPoint file formats

Applies to: Skype for Business 2016


In the PowerPoint File Block Settings, you block opening or saving for PowerPoint 97-2003 Presentations, Shows, Templates, and Add-in FilesWhen you try to share a PowerPoint presentation in Microsoft Skype for Business 2016, even when an Office Online Server is used to present the file, the presentation fails.


Skype for Business, for compatibility with legacy clients, exports PowerPoint files by using this legacy format. When the format is blocked, the export fails. This causes the sharing process to fail.


To fix this issue, install the October 6, 2020, update (KB4486669) for Microsoft Skype for Business 2016.


Enabling this fix will break compatibility with Lync Server 2010 and earlier clients. Users can still join via the Skype for Business Web App if their client is not compatible.

To enable this fix, create a policy by using one of the following options:
  1. Create the following registry key on the client computers:

    Key: Software\Policies\Microsoft\Office\16.0\Lync
    Value Type: DWORD
    Value Name: DisableGenerationOfLegacyPPTFiles
    Value Data: 0x00000001
  2. Create the following client policy entry by using the Skype for Business PowerShell:

    $x = New-CsClientPolicyEntry -Name "DisableGenerationOfLegacyPPTFiles" -Value "true"
    Set-CsClientPolicy -Identity "<ClientPolicyName>" -PolicyEntry @{Add=$x}