Information
This policy setting determines if Excel files in Outlook attachments open in Protected View.
The recommended state for this setting is: Disabled.
Rationale:
Opening files that do not require Protected View could lead to malicious code executing on a user's computer or the network.
Impact:
Some functionality is not available when files are opened in Protected View; users will be unable to edit the file.
Solution
To establish the recommended configuration via GP, set the following UI path to Disabled.
User Configuration\Administrative Templates\Microsoft Excel 2016\Excel Options\Security\Trust Center\Protected View\Turn off Protected View for attachments opened from Outlook
Default Value:
Disabled. (Outlook attachments open in Protected View.)