Information
File attachments from Outlook must be opened in Excel in Protected mode.
GROUP ID: V-223343
RULE ID: SV-223343r961092
This policy setting allows you to determine if Excel files in Outlook attachments open in Protected View.
If you enable this policy setting, Outlook attachments do not open in Protected View.
If you disable or do not configure this policy setting, Outlook attachments open in Protected View.
Solution
Set policy value for
User Configuration >> Administrative Templates >> Microsoft Excel 2016 >> Excel Options >> Security >> Trust Center >> Protected View >> Turn off Protected View for attachments opened from Outlook
to 'Disabled'.