Outlook must be configured not to prompt users to choose security settings if default settings fail.

Check to prompt the user to choose security settings if default settings fail; uncheck to automatically select.

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security "Prompt user to choose security settings if default settings fail" is set to "Disabled".

Procedure: Use the Windows Registry Editor to navigate to the following key:

HKCU\Software\Policies\Microsoft\Office\16.0\outlook\security

Criteria: If the value ForceDefaultProfile is REG_DWORD = 0, this is not a finding.

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security "Prompt user to choose security settings if default settings fail" to "Disabled".