How to fix blocked access to windows security

Blocked access to Virus & threat protection in Windows Security is usually caused by security settings, third‑party security software, or damaged configuration. Use these steps to restore access on Windows 11:

1. Check that core Windows security features are enabled
   • Open the Windows Security app.
   • Go to Virus & threat protection → Manage settings.
   • Ensure key protections are turned on, especially:
     • Cloud-delivered protection
     • Automatic sample submission These settings are required for features such as block at first sight and indicate that Microsoft Defender Antivirus is active.
2. Verify Windows Firewall is not disabled by policy
   • In Windows Security, select Firewall & network protection or use this shortcut: windowsdefender://network/.
   • For the active network profile (Domain, Private, or Public), make sure Microsoft Defender Firewall is set to On.
   • If the switches are greyed out or say they are managed by an organization, the device may be managed by policy and changes must be made by the administrator.
3. Check Controlled folder access if apps are being blocked If the issue is that apps cannot access files and Windows Security reports blocked actions:
   • In Windows Security, go to Virus & threat protection → Ransomware protection → Controlled folder access.
   • If Controlled folder access is On and blocking a known‑good app:
     • Select Protected folders (or use windowsdefender://protectedfolders/) to review which folders are protected.
     • Select Allow an app through Controlled folder access (or use windowsdefender://allowappthroughfolder/) and add the trusted app.
   • Be cautious: any app added here will be able to change files in protected folders.
4. Automatically repair common Windows security settings (Windows 10 only) If the issue is on a Windows 10 machine (or for reference on a similar device):
   • Download and run the Windows Security Troubleshooter from the Automatically fix Windows security issues article.
   • It checks and can re‑enable:
     • Phishing/SmartScreen Filter
     • User Account Control (UAC)
     • Data Execution Prevention (DEP)
     • Windows Firewall
     • Antivirus protection status and updates Note: MSDT troubleshooters are deprecated and will be removed from future Windows versions.
5. If Windows Security is still blocked or missing
   • If Virus & threat protection remains inaccessible, or Defender appears removed or broken after an update, an in‑place repair/Reset this PC may be required (not detailed in the provided context). On some systems, Windows Defender functionality has been restored automatically after subsequent cumulative or preview updates.

If the device is joined to a domain or managed (for example by an organization or school), some Windows Security areas can be intentionally blocked by policy; in that case, the administrator must adjust those policies.

References:

• Turn on block at first sight
• Firewall and Network Protection in the Windows Security App
• Virus and Threat Protection in the Windows Security App
• Automatically fix Windows security issues
• After i updated windows 10 to windows 11 my windows defender got deleted. - Microsoft Q&A