How to Block Files Downloaded from Internet in Windows 11

How Does Windows Decide What to Block?

Windows looks at three things to decide if it should block a file:

• What program you are using
• What type of file it is
• Where you downloaded it from (Internet, local network, trusted sites, or restricted sites)

File Risk Levels

Windows assigns different risk levels, like High or Medium, to files you download so you know how safe they are. High-risk files from the internet will show a warning that Windows thinks they could be harmful, while medium-risk files will ask you to confirm before opening.

• High Risk – Windows stops you from opening these files if they come from a restricted zone. If they come from the Internet, you see a warning that says “Windows found that this file is potentially harmful.”
• Medium Risk – Windows warns you and asks if you really want to run this software.
• Low Risk – Windows lets you open these files without any warning.

What Happens If You Disable File Blocking?

If you turn off Windows’ file blocking, your computer won’t be able to tell if downloaded files are risky, which can lead to security problems.

Option 1Use Local Group Policy Editor

You can block files downloaded from the internet using the Local Group Policy Editor if your Windows 11 is Pro, Enterprise, or Education. This tool lets you change security settings for your computer, allowing you to decide if this blocking applies to everyone or just specific users.

1. Open the Local Group Policy Editor. Choose whether you want this to apply to all users, specific users, or all users except administrators.
2. In the left pane, go to this location:
   
   User Configuration\Administrative Templates\Windows Components\Attachment Manager
3. Look at the right pane. Find the policy called "Do not preserve zone information in file attachments." Double-click it to edit it.
4. To Turn ON File Blocking (Default Setting):
   
   Select the dot next to "Not Configured" and click OK.
   

5. To Turn OFF File Blocking:
   
   Select the dot next to "Enabled" and click OK.
   

6. You can close the Local Group Policy Editor.

Option 2Use Registry Editor (All 🪟 Windows 11 Versions)

You can block files downloaded from the internet on any Windows 11 version, even Home, by using the Registry Editor. This method needs administrator access, and you'll use Windows Terminal with a special command to change the registry settings and turn on file blocking.

Right-click the Windows Terminal app and select "Run as administrator."

To Turn ON File Blocking (Default Setting):

reg delete "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments" /v SaveZoneInformation /f
reg delete "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Attachments" /v SaveZoneInformation /f

To Turn OFF File Blocking:

reg add "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments" /v SaveZoneInformation /t REG_DWORD /d 1 /f
reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Attachments" /v SaveZoneInformation /t REG_DWORD /d 1 /f

Press Enter to run the command.

Summary

Windows helps keep you safe by blocking dangerous files downloaded from the internet, using a system that checks where files come from and their type.