Windows Defender updates (malware definitions and engine updates) don't run on the same schedule as other Windows updates-- they're downloaded at least three t

Windows Defender updates (malware definitions and engine updates) don't run on the same schedule as other Windows updates-- they're downloaded at least three times daily, and installed immediately once they're downloaded. IIRC, they're also not disabled by the UI switch that disables other Windows updates. A user would have to go pretty far out of their way in mucking around with things that shouldn't be mucked around with in order for this update to take "weeks" to propagate to them.