Turn off Protected View for attachments opened from Outlook
This per-user policy setting determines whether Word files opened as Outlook attachments initially open in Protected View.
since 0.9.8.11
Purpose
Show registry keys (1)
HKCU\software\policies\microsoft\office\16.0\word\security\protectedview\disableattachmentsinpv
This per-user policy setting determines whether Word files opened as Outlook attachments initially open in Protected View.
The value uses the REG_DWORD data type. A value of 1 causes affected attachments to bypass Protected View. With a value of 0, or when the value is absent, they open in Protected View unless another security decision blocks or otherwise restricts the file.
Protected View is a restricted, read-only mode in which most editing functions are unavailable. It allows users to inspect potentially unsafe files before explicitly enabling editing.
Notes
Security
A value of 1 removes a layer of protection from Word attachments opened from Outlook. Such files open outside Protected View without first being presented in its restricted environment. A malicious or unexpected email attachment can therefore pose a greater risk, for example by exploiting a Word vulnerability or inducing the user to perform an unsafe action.
This setting does not automatically enable macros, ActiveX controls, or other active content. Applicable macro security, File Block, Office File Validation, and other Trust Center policies remain in effect.
Possible side effects
When Protected View is bypassed, normal Word functionality is generally available immediately unless other security controls, permissions, or document restrictions limit it. Affected attachments no longer receive the initial read-only experience and security warning provided by Protected View.
Notes
This setting applies only to Word and only to the user represented by the HKCU registry branch. Equivalent Excel and PowerPoint policies use separate registry paths and are not changed by this value.
It does not disable Protected View in every scenario. Independent controls such as File Block settings or Office File Validation can still block a file or cause it to open in a restricted mode.
Microsoft documentation
Microsoft Support: What is Protected View?
Microsoft Learn: Policies for Microsoft 365 Apps