How to set up and use Windows 11 Sandbox to safely test untrusted applications and files

Summary

This guide helps you troubleshoot and resolve: How to set up and use Windows 11 Sandbox to safely test untrusted applications and files. Follow the steps below to fix the issue.

Common Causes

Windows 11 Sandbox is a lightweight, isolated virtual environment built into Windows 11 Pro, Enterprise, and Education editions. It provides a clean, temporary desktop where you can safely open untrusted applications, suspicious email attachments, or unfamiliar files without putting your main operating system at risk. Anything you do inside the Sandbox stays contained, and the entire environment is discarded the moment you close it.

This makes Sandbox an excellent tool for testing software downloaded from unfamiliar sources, previewing potentially malicious attachments, or simply experimenting with applications before installing them on your primary machine. This guide will walk you through enabling Windows Sandbox, launching it, and using it effectively.

Before You Begin

Windows Sandbox has a few system requirements that must be met before you can use it:

• Edition: Windows 11 Pro, Enterprise, or Education (Sandbox is not available on Windows 11 Home)
• Processor: 64-bit CPU with virtualisation support (most modern CPUs qualify)
• RAM: At least 4 GB (8 GB or more recommended)
• Disk Space: At least 1 GB of free space
• Virtualisation: Enabled in your BIOS/UEFI settings

Enabling Windows Sandbox

Step 1: Open Windows Features

1. Press Win + R to open the Run dialog
2. Type optionalfeatures and press Enter
3. The Windows Features dialog will open

Step 2: Turn on Windows Sandbox

1. Scroll through the list and locate Windows Sandbox
2. Tick the checkbox next to it
3. Click OK
4. Wait while Windows downloads and installs the required components
5. When prompted, click Restart now to complete the installation

Step 3: Verify Virtualisation is Enabled

If Sandbox fails to launch, virtualisation may be disabled in your BIOS. To check this in Windows:

1. Press Ctrl + Shift + Esc to open Task Manager
2. Click the Performance tab
3. Select CPU on the left
4. Look for Virtualisation in the bottom-right corner — it should say Enabled

If virtualisation is disabled, you will need to restart your computer, enter the BIOS/UEFI settings (commonly by pressing F2, F10, Del, or Esc during startup), and enable the option labelled Intel VT-x, AMD-V, or SVM Mode.

Launching and Using Windows Sandbox

Starting the Sandbox

1. Click the Start button
2. Type Windows Sandbox in the search bar
3. Select Windows Sandbox from the results
4. A new window will open displaying a clean Windows 11 desktop

Getting Files into the Sandbox

Windows Sandbox runs in isolation, so it cannot directly access your main system files. To test a file or application, you need to copy it into the Sandbox first:

Method 1: Copy and Paste

1. Locate the file on your main desktop or in File Explorer
2. Right-click the file and select Copy
3. Click into the Sandbox window
4. Right-click on the Sandbox desktop and select Paste

Method 2: Drag and Drop

1. Click and hold the file from your main desktop
2. Drag it directly into the Sandbox window
3. Release to drop the file onto the Sandbox desktop

Method 3: Share a Folder (Advanced)

For ongoing testing, you can configure Sandbox to map a folder from your host system. This requires creating a configuration file:

1. Open Notepad on your main system
2. Paste the following content:

   <Configuration>
     <MappedFolders>
       <MappedFolder>
         <HostFolder>C:\Users\YourName\Desktop\TestFiles</HostFolder>
         <SandboxFolder>C:\Users\Public\TestFiles</SandboxFolder>
         <ReadOnly>false</ReadOnly>
       </MappedFolder>
     </MappedFolders>
   </Configuration>

   Replace C:\Users\YourName\Desktop\TestFiles with the actual folder path you wish to share.

3. Save the file with the extension .wsb (for example, SandboxConfig.wsb). When saving in Notepad, set the Save as type to All Files so the extension is not changed to .txt.
4. Double-click the saved .wsb file to launch Sandbox with your folder mapped

Testing Your File or Application

1. Once your file is on the Sandbox desktop, double-click it to open or run it
2. Observe the behaviour carefully — watch for unexpected network activity, unusual system prompts, or suspicious file changes
3. If you need to install software, proceed normally; the installation will only affect the Sandbox environment
4. You can use the Sandbox's built-in web browser to test links or download additional files

Closing the Sandbox

1. When you have finished testing, close the Sandbox window by clicking the X
2. Confirm you wish to close the Sandbox when prompted
3. All contents, changes, and installed programs inside the Sandbox will be permanently discarded

Best Practices for Using Windows Sandbox

• Test before you trust: Use Sandbox to evaluate any software downloaded from unfamiliar websites or shared via email
• Examine email attachments: Open suspicious attachments in Sandbox first to confirm they are safe
• Browse risky websites: Use Sandbox's browser to visit links you are uncertain about
• Keep it short: Sandbox is designed for quick, disposable testing — not for long-term use
• Don't store important data: Never save documents or credentials inside Sandbox, as they will be lost when it closes

Troubleshooting

Sandbox option is missing from Windows Features

This usually means you are running Windows 11 Home. Sandbox is only available on Pro, Enterprise, and Education editions. You will need to either upgrade your edition or use an alternative virtualisation solution.

Sandbox fails to start with error 0x80070520

This error typically indicates that virtualisation is disabled in your BIOS. Restart your computer, enter the BIOS/UEFI settings, and enable virtualisation (Intel VT-x or AMD-V/SVM).

Sandbox window opens but is unresponsive

Ensure your system meets the minimum requirements, particularly RAM. Close other resource-intensive applications and try launching Sandbox again.

Files copied into Sandbox appear corrupted

Very large files may fail to copy into Sandbox reliably. Try compressing the file into a ZIP archive first, then copying the archive into Sandbox and extracting it inside.

Sandbox cannot access the internet

By default, Sandbox has network access. If it is not connecting, check your host system's network connection and firewall settings. You can also disable network access entirely by adding a <Networking>Disable</Networking> entry to your .wsb configuration file if you want to test files in a fully offline environment.

Clipboard sharing does not work

Clipboard sharing between the host and Sandbox is enabled by default but can be disabled in a .wsb configuration file. If copying and pasting is not working, ensure no custom .wsb file is overriding this setting, and try restarting both the Sandbox and the host application you are copying from.

Still Having Issues?