0x800704EC: This program is blocked by group policy (Windows Defender)
Windows Security/Defender can’t start because another antivirus or a group policy has turned it off.
Seen on:
Windows
Meaning
Installing third-party antivirus disables Defender by policy; uninstalling it badly leaves DisableAntiSpyware policies behind. Corporate GPOs can also block it.
Common causes
- Third-party antivirus installed (or remnants)
- DisableAntiSpyware/DisableRealtimeMonitoring policy set
- Corporate group policy
⚡ Quick fix
- Remove leftover antivirus with its removal tool
- Delete the Defender policy keys
- Run gpupdate /force on domain machines
Detailed fix by platform
Windows
- powershell
reg query "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender" reg delete "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender" /v DisableAntiSpyware /f
How to diagnose
- Policy — Defender policy keys
- AV — Other security software installed?
🔧 Still not fixed?
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Last updated 7 Oct 2026