This policy setting allows you to configure monitoring for incoming and outgoing files, without having to turn off monitoring entirely. It is recommended for use on servers where there is a lot of incoming and outgoing file activity but for performance reasons need to have scanning disabled for a particular scan direction. The appropriate configuration should be evaluated based on the server role. Note: that this configuration is only honored for NTFS volumes. For any other file system type, full monitoring of file and program activity will be present on those volumes. The options for this setting are mutually exclusive: 0 = Scan incoming and outgoing files (default) 1 = Scan incoming files only 2 = Scan outgoing files only Any other value, or if the value does not exist, resolves to the default (0). If you enable this setting, the specified type of monitoring will be enabled. If you disable or do not configure this setting, monitoring for incoming and outgoing files will be enabled. Countermeasure: Configure this setting depending on your organization's requirements. Potential Impact: Scanning incoming or outgoing files can impact server performance.

[bi-directional (full on-screen)/scan only incoming (disable on-open)/scan only outgoing (disable on-close)]

(1) GPO: Computer Configuration\Administrative Templates\Windows Components\Windows Defender\Real-time Protection\Configure monitoring for incoming and outgoing file and program activity (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows Defender\Real-Time Protection!RealtimeScanDirection