Omega007 Please find some options below:

Use GPO to enforce default file save formats

• If the default file save formats are set through GPO the prompt will not be shown.
• When set through GPO, the user can not change them afterwards.
• How to
• Enable the following settings:
• “Microsoft Excel 2016\Excel Options\Save > Default file format” set to “Excel Workbook (*.xlsx)”
• “Microsoft PowerPoint 2016\PowerPoint Options\Save > Default file format” set to “PowerPoint Presentation (*.pptx)
• “Microsoft Word 2016\Word Options\Save > Default file format” set to “Word Document (*.docx)”

Mark the file prompt as “already shown”

• You can also inject a regkey which marks the file format prompt as already shown
• Injection can be done through e.g. Group Policy Preferences (“apply once”)
• User can change the file formats on their own
• HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Common\General > ShownFileFmtPrompt
• DWORD
• Value: 0x1 (1)