Information
This policy setting governs the default format for new presentation files that users create.
The recommended state for this setting is: Enabled: PowerPoint Presentation (*pptx)
If a new PowerPoint file is created in an earlier format, some users may not be unable to open or use the file, or they may choose a format that is less secure than the PowerPoint format.
Solution
To establish the recommended state via configuration profiles, set the following Settings Catalog path to Enabled: PowerPoint Presentation (*pptx) :
Microsoft PowerPoint 2016\PowerPoint Options\Save\Default file format
Impact:
Enabling this setting does not prevent users from choosing a different file format for a new PowerPoint file, therefore it is unlikely to affect usability for most users.