SmartScreen is meant to block known risky apps and sites, so when it stops working you lose an important layer of protection — the problem is SmartScreen doesn’t work in Windows 10. This can be caused by a turned-off setting, group policy or registry overrides, network blocking, corrupted system files, or interference from third-party security software. In this article you’ll learn the most common causes and step-by-step fixes to restore SmartScreen protection.
Key Takeaway
If SmartScreen doesn’t work, check the simplest settings first: open Windows Security > App & browser control and ensure SmartScreen options are enabled; if that does not help, verify Group Policy/registry settings, confirm network access to Microsoft reputation servers, repair system files with SFC/DISM, and temporarily disable third-party antivirus to test for conflicts.
Quick Fix Guide
| Reason for the Problem | Quick Solution |
|---|---|
| SmartScreen is turned off in Settings | Enable it in Windows Security > App & browser control. |
| Group Policy blocks SmartScreen | Re-enable via gpedit.msc: Computer Configuration > Administrative Templates > Windows Components > File Explorer or Windows Defender. |
| Registry keys override SmartScreen | Restore or delete blocking keys under HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows. |
| Outdated Windows 10 build | Install cumulative updates via Settings > Update & Security > Windows Update. |
| Third-party antivirus conflicts | Temporarily disable/uninstall third-party AV and test SmartScreen. |
| Network or proxy blocks SmartScreen servers | Allow outbound HTTPS to SmartScreen endpoints or disable restrictive proxy. |
| Required Windows services are stopped | Start Security Center and related services in services.msc. |
| Browser-specific SmartScreen is disabled | Turn on SmartScreen in Microsoft Edge > Settings > Privacy, search, and services. |
| User Account Control (UAC) is disabled | Re-enable UAC from Control Panel > User Accounts > Change User Account Control settings. |
| Corrupted system files or profile | Run sfc /scannow and DISM commands; test with a new user account. |
Detailed Fixes for “SmartScreen doesn’t work in Windows 10”
1. SmartScreen is turned off in Settings
Why it causes the problem
- SmartScreen is controlled by Windows Security (App & browser control). If the user or an app turned it off, Windows won’t check file or web reputation.
Step-by-step solution
- Open Start > Settings > Update & Security > Windows Security or type Windows Security in Start.
- Click App & browser control.
- Under Check apps and files, select Warn or Block instead of Off.
- Under SmartScreen for Microsoft Edge and Potentially unwanted app blocking, turn settings on as desired.
Notes: If options are greyed out, a policy or registry setting is likely controlling SmartScreen (see reasons 2 and 3).
2. Group Policy disables SmartScreen
Why it causes the problem
- Enterprise or local Group Policy can force SmartScreen off or prevent changes, making the UI appear disabled.
Step-by-step solution
- Press Win + R, type gpedit.msc, and press Enter.
- Navigate to Computer Configuration > Administrative Templates > Windows Components > File Explorer.
- Find Configure Windows Defender SmartScreen and set it to Not Configured or configure it to Enabled and pick the desired level.
- Also check Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender SmartScreen (if present).
- Apply changes and run gpupdate /force in an elevated Command Prompt.
Notes: On Windows 10 Home, the Group Policy editor is not available; use the registry fix in reason 3.
3. Registry keys override SmartScreen
Why it causes the problem
- Policies can be set in the registry to disable SmartScreen; corrupt or incorrect keys will keep it off.
Step-by-step solution
- Press Win + R, type regedit, and press Enter.
- Back up the registry: File > Export and choose a location.
- Check these locations for SmartScreen-related policy keys:
- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System — look for EnableSmartScreen (DWORD 0 = off, 1 = on).
- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Explorer — look for SmartScreen keys.
- If you find values forcing SmartScreen off, delete the value or set it to the recommended value (e.g., EnableSmartScreen = 1) then reboot.
- If unsure, export the key and then delete it; test SmartScreen again.
Warning: Editing the registry can affect system stability. Back up before changes.
4. Outdated Windows 10 build
Why it causes the problem
- An older Windows 10 build may contain bugs or lack the SmartScreen integrations that newer updates fixed.
Step-by-step solution
- Open Settings > Update & Security > Windows Update.
- Click Check for updates and install anything available.
- Optionally, review View update history or install any pending cumulative updates.
Notes: Some SmartScreen server interactions depend on up-to-date TLS stacks and OS fixes; keeping Windows updated reduces compatibility problems.
5. Third-party antivirus or security suite interference
Why it causes the problem
- Some security products disable Windows Defender components or intercept certificate/reputation checks, which can break SmartScreen.
Step-by-step solution
- Temporarily disable real-time protection in the third-party AV (use the product’s interface).
- Test SmartScreen by downloading and running a known safe executable (or use Microsoft’s test guidance).
- If SmartScreen works when the AV is disabled, consider adding exception settings, updating the AV, or switching products.
- To test comprehensively, uninstall the security app via Settings > Apps, reboot, and test again.
Notes: Many third-party AVs register as the system’s primary protection and intentionally disable Defender features; consult the vendor for best compatibility settings.
6. Network or proxy blocking SmartScreen servers
Why it causes the problem
- SmartScreen needs to contact Microsoft reputation servers over HTTPS; a firewall, proxy, or DNS block will prevent lookups.
Step-by-step solution
- Test connectivity to Microsoft endpoints using PowerShell as admin: Test-NetConnection -ComputerName reputation.smartscreen.microsoft.com -Port 443
- If tests fail, check company firewall rules, router settings, or local host file (C:\Windows\System32\drivers\etc\hosts) for blocks.
- In Settings > Network & Internet > Proxy, ensure a faulty proxy isn’t set, or disable proxy to test.
- Allow outbound HTTPS (port 443) to Microsoft services in your firewall or proxy; if on corporate network, contact IT.
Notes: Some corporate environments intentionally block SmartScreen for policy reasons; coordinate with network administrators.
7. Required Windows services are stopped
Why it causes the problem
- SmartScreen depends on system services (like Security Center) to report status and operate correctly.
Step-by-step solution
- Press Win + R, type services.msc, and press Enter.
- Find Security Center (service name wscsvc) and ensure it is Running and set to Automatic.
- Also check Windows Defender Firewall and Windows Defender Antivirus Service (WinDefend) where applicable.
- If a service is stopped, right-click > Start; if startup type is incorrect, right-click > Properties and set Startup type to Automatic.
Notes: If services won’t start, check the Event Viewer for errors (Event Viewer > Windows Logs > System).
8. Browser-specific SmartScreen is disabled
Why it causes the problem
- Microsoft Edge (and historically Internet Explorer) has its own SmartScreen controls; the Windows-level SmartScreen might be fine but the browser won’t block malicious web content.
Step-by-step solution (Microsoft Edge)
- Open Microsoft Edge > Settings > Privacy, search, and services.
- Ensure Microsoft Defender SmartScreen is toggled On.
- For Internet Explorer-based checks, open Internet Options > Advanced and check related security settings.
Notes: If using Chrome or Firefox, they have separate safe-browsing systems; SmartScreen only applies to Edge/IE for web content.
9. User Account Control (UAC) is disabled or set too low
Why it causes the problem
- SmartScreen sometimes relies on elevation prompts and UAC to block or warn about application execution; disabling UAC can reduce these protections.
Step-by-step solution
- Open Control Panel > User Accounts > Change User Account Control settings.
- Move the slider to the default: Notify me only when apps try to make changes to my computer (default) or higher.
- Click OK and restart if prompted.
Notes: Lowering UAC is not recommended — it weakens multiple Windows security features, not only SmartScreen.
10. Corrupted system files or user profile
Why it causes the problem
- Corrupted system files can break SmartScreen integration; a damaged user profile may also prevent UI elements from displaying correctly.
Step-by-step solution
- Open an elevated Command Prompt (right-click Start > Command Prompt (Admin) or Windows PowerShell (Admin)).
- Run sfc /scannow and wait for the process to complete.
- If SFC finds errors it cannot fix, run these DISM commands in order:
- DISM /Online /Cleanup-Image /CheckHealth
- DISM /Online /Cleanup-Image /ScanHealth
- DISM /Online /Cleanup-Image /RestoreHealth
- After DISM finishes, run sfc /scannow again.
- If issues persist, create a new local administrator user: Settings > Accounts > Family & other users > Add someone else to this PC, then test SmartScreen under that account.
Notes: Running SFC/DISM can take some time; ensure an internet connection for DISM to fetch replacement files.
Additional maintenance and prevention
- Keep Windows and Edge up to date and enable automatic updates (Settings > Update & Security > Windows Update).
- Avoid editing registry/policy settings unless necessary; document changes you make.
- Use a reputable security product that is known to coexist with Windows Defender (check vendor guidance for “compatibility with Windows Defender”).
- Periodically run sfc /scannow and a full antivirus scan to catch corruption or malware that could disable SmartScreen.
FAQ
What happens if SmartScreen is permanently blocked by company policy?
If your IT department applied policies that disable SmartScreen, contact them — only they can change the Group Policy or MDM configuration; you can request an exception or explanation of the security posture.
Can I reset only SmartScreen without reinstalling Windows?
Yes — try removing SmartScreen-related registry policy keys, re-enabling in Windows Security, and running sfc /scannow and DISM; these steps often repair SmartScreen without a full reinstall.
Will reinstalling Microsoft Edge fix SmartScreen issues in the browser?
Reinstalling or resetting Edge can restore browser-specific SmartScreen settings: Edge > Settings > Reset settings > Restore settings to their default values. Reinstalling the app using the official installer is also effective.
Does SmartScreen require a Microsoft account?
No — SmartScreen works with local accounts too. However, some telemetry and syncing features are better with a Microsoft account; SmartScreen reputation checks do not require you to be signed in.
How can I test that SmartScreen is working after fixes?
Download a harmless test file known to trigger SmartScreen (Microsoft or reputable security vendors sometimes provide safe test files) or use browser test pages. Alternatively, temporarily create a new executable and run it; SmartScreen should show a warning for unknown apps by default if settings are enabled.
SmartScreen is a simple but important layer of protection and most failures are due to settings, policies, or network blocks — checking Windows Security > App & browser control, Group Policy/registry, network connectivity, and running SFC/DISM usually restores functionality. If you followed these steps and still have trouble, consult your system administrator or Microsoft support for further diagnostics of SmartScreen doesn’t work in Windows 10.
