Define the maximum size of downloaded files and attachments to be scanned

Policy ID: RealtimeProtection_IOAVMaxSize
Scope: Computer Configuration
Supported on: At least Windows Server 2012, Windows 8 or Windows RT
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: Windows Components › Microsoft Defender Antivirus › Real-time Protection

Description

This policy setting defines the maximum size (in kilobytes) of downloaded files and attachments that will be scanned.

If you enable this setting, downloaded files and attachments smaller than the size specified will be scanned.

If you disable or do not configure this setting, a default size will be applied.

ComputerHKEY_LOCAL_MACHINE