Windows Firewall is a core security layer in Windows 10 and Windows 11, but it can fail silently, refuse to start, or ignore your rules.
This guide explains how to fix Windows Firewall not working with clear checks, built-in repair tools, and service-level troubleshooting.
What Windows Firewall Does and Why It Stops Working
Windows Firewall, also called Microsoft Defender Firewall in newer versions of Windows, filters inbound and outbound network traffic based on rules.
When it fails, your PC may lose protection against unauthorized connections, app access prompts may disappear, or network sharing and remote access may behave unpredictably.
Common causes include corrupted system files, disabled services, conflicting security software, damaged firewall policies, Windows updates, Group Policy restrictions, or third-party antivirus suites that replace Microsoft’s firewall layer.
Check Whether Windows Firewall Is Actually Turned On
Before deeper repair steps, confirm that the firewall is enabled for the active network profile.
- Open Settings and go to Privacy & security or Update & Security, depending on your Windows version.
- Select Windows Security and open Firewall & network protection.
- Review Domain network, Private network, and Public network.
- Make sure the firewall toggle is set to On for the profile you are using.
If the interface says a setting is managed by your organization, the device may be controlled by Group Policy or MDM, and local changes may not persist.
Restart the Core Firewall Services
Windows Firewall depends on background services such as Base Filtering Engine and Windows Defender Firewall.
If either service is stopped, the firewall may not function correctly.
- Press Win + R, type services.msc, and press Enter.
- Find Base Filtering Engine.
- Ensure its Startup type is set to Automatic and the service is running.
- Find Windows Defender Firewall.
- Set it to Automatic and start the service if it is stopped.
If either service fails to start, note the error message.
Service failure often points to corrupted system files or policy conflicts that require further repair.
Use the Built-in Firewall Troubleshooter
Windows includes automatic diagnostics that can detect common networking and security issues.
While it may not fix every fault, it is fast and worth trying early.
- Open Settings.
- Go to System and then Troubleshoot.
- Select Other troubleshooters.
- Run the Network Adapter and Internet Connections troubleshooters if available.
For Windows Security issues, Microsoft also provides a support and recovery path through the Get Help app and the Microsoft Support and Recovery Assistant, which can detect security component problems.
Reset Windows Firewall to Default Settings
Custom firewall rules can break normal behavior, especially after software installs, VPN use, or manual rule changes.
Resetting restores Microsoft’s default configuration and removes problematic custom rules.
Reset from the Windows Security interface
- Open Windows Security.
- Select Firewall & network protection.
- Choose Restore firewalls to default.
- Confirm the reset.
Reset from the classic Control Panel
- Open Control Panel.
- Go to System and Security and then Windows Defender Firewall.
- Select Restore defaults.
Use this step when you suspect rule corruption, but remember that it removes custom allow rules for apps and ports.
Repair Corrupted System Files
System file damage can prevent security components from loading correctly.
The two most useful repair commands are SFC and DISM.
Run System File Checker
- Open Command Prompt or Windows Terminal as administrator.
- Run: sfc /scannow
- Wait for the scan to complete and follow any repair instructions.
Run DISM if SFC cannot fix everything
- Open an elevated terminal.
- Run: DISM /Online /Cleanup-Image /RestoreHealth
- After DISM finishes, run sfc /scannow again.
DISM repairs the Windows component store, which can resolve deeper corruption affecting Windows Defender Firewall, network stacks, and related services.
Check for Conflicts with Third-Party Antivirus or VPN Software
Many security suites install their own firewall module or disable Microsoft Defender Firewall to avoid conflicts.
VPN clients, endpoint protection tools, and network filters can also interfere with Windows Firewall behavior.
- Temporarily disable or uninstall third-party antivirus software to test whether the issue disappears.
- Review any built-in firewall or web protection features in suites such as Norton, McAfee, Bitdefender, Avast, or Kaspersky.
- Uninstall VPN clients if they add network filtering drivers or custom routing rules.
If Windows Firewall starts working after removal, the third-party product is likely the cause.
Reinstall only after confirming it integrates cleanly with Microsoft Defender Firewall.
Review Group Policy and Registry Settings
On Pro, Enterprise, and Education editions, Group Policy can disable the firewall or override local rules.
Registry-based tweaks from optimization tools can do the same.
Group Policy checks
- Press Win + R, type gpedit.msc, and press Enter.
- Navigate to Computer Configuration > Administrative Templates > Network > Network Connections > Windows Defender Firewall.
- Review domain, private, and public profile policies.
Look for settings that disable the firewall or block profile inheritance.
If the device belongs to a business network, IT policy may be intentional and should not be changed without permission.
Registry caution
Avoid editing the registry unless you know the exact key and expected value.
Incorrect changes can damage networking or security subsystems.
If you suspect registry corruption, use a restore point or system image before making changes.
Install the Latest Windows Updates
Microsoft frequently ships fixes for Defender platform components, firewall policy bugs, and networking issues.
A pending update can leave security services partially broken.
- Open Settings and go to Windows Update.
- Check for updates and install all available cumulative updates.
- Restart the PC after installation, even if Windows does not require it immediately.
If the problem began after a recent update, use Update history to identify the change.
In rare cases, rolling back a specific update may restore firewall functionality.
Reset the Network Stack When Firewall Problems Affect Connectivity
Sometimes Windows Firewall appears broken because the TCP/IP stack, Winsock catalog, or network adapters are damaged.
A network reset can clear that layer.
- Open Settings.
- Go to Network & internet.
- Select Advanced network settings.
- Choose Network reset.
You can also run these administrator commands:
- netsh winsock reset
- netsh int ip reset
Restart the computer after running the commands.
This step is especially useful when firewall symptoms overlap with lost connectivity, VPN failures, or adapter issues.
How to Confirm the Fix Worked
After troubleshooting, verify that the firewall is active and enforcing rules.
Open Windows Security, confirm all active profiles show protection enabled, and test with a known blocked app or inbound connection attempt.
- Check that the Windows Defender Firewall service is running.
- Confirm the correct profile is active for your network.
- Review allowed apps and inbound rules for anything recently changed.
- Reboot once more to ensure settings persist after startup.
If the firewall remains disabled after all these steps, the issue is likely tied to domain policy, persistent security software, or deeper Windows corruption that may require an in-place repair install.