Always open untrusted text-based files in Protected View

This policy setting controls whether text-based files (.csv, .dif, and .sylk) opened from an untrusted location are always opened in Protected View. If you enable this policy setting, text-based files opened from an untrusted location are always opened in Protected View. Users will not be able to change this setting under File > Options > Trust Center > Trust Center Settings > Protected View. If you disable or don’t configure this policy setting, text-based files opened from an untrusted location are not opened in Protected View, unless users have changed this setting in the Trust Center. Note: This policy setting only applies to subscription versions of Office, such as Microsoft 365 Apps for enterprise.