Information
This policy setting controls whether hidden markup is visible when users open PowerPoint files in standard or HTML format. The recommended state for this setting is: Enabled. PowerPoint presentations that are saved in standard or HTML format can contain a flag indicating whether markup (comments or ink annotations) in the presentation should be visible when the presentation is open. By default, PowerPoint ignores this flag when opening a file, and always displays any markup present in the file. In addition, when saving a file, PowerPoint sets the flag to display markup when the presentation is next opened. If this default configuration is changed, PowerPoint sets the flag according to the state of the Show Markup option on the Review tab of the Ribbon when it saves presentations in standard or HTML format. In addition, PowerPoint enables or disables the Show Markup option according to the way the flag is set when it opens files, which means that a presentation saved with hidden markup is opened with the markup still hidden. If a file is saved with hidden markup, users might inadvertently distribute sensitive comments or information to others via the presentation file.
Solution
To implement the recommended configuration state, set the following Group Policy setting to Enabled. User Configuration\Administrative Templates\Microsoft PowerPoint 2016\PowerPoint Options\Security\Make Hidden Markup Visible Impact: If this setting is Enabled, hidden markup will be visible when the file is opened, and if users intend it to be hidden they will need to hide it again. (Users can permanently locate and remove undesired markup from files by using the Document Inspector feature in PowerPoint.) Enabling this setting enforces the default configuration in PowerPoint. In most cases, markup is intended to be visible to users. Markup does not display in presentation mode in PowerPoint, even if it is visible in design mode, so it is likely that this setting will have a minimal impact on usability.