Windows Sandbox lets you test software you don’t fully trust. You can install and run programs and apps inside it to see what happens, without risking your real computer.
There are plenty of times when you’ll download something you’re not sure about. It might come from an untrustworthy source, such as one of those file download websites, or a link someone sent you.
Free programs often come bundled with extra, unwanted programs or add-ons that are hard to get rid of. Whatever the reason, wherever you got the software, it’s well worth testing it in Windows Sandbox before you let it loose on your real computer.
Windows Sandbox is part of Windows 11 and 10 Pro, Enterprise and Education. It isn’t available on the Home editions. If your PC has one of the three, here’s how to enable Windows Sandbox. It takes a couple of minutes.
If you have Windows Home, all is not lost. You can set up a free Windows 11 virtual machine in VirtualBox instead, and there are more free options near the end of this guide.
The Short Version
- Open Windows Sandbox from the Start menu.
- On your PC, right-click the file you want to test and click Copy.
- Click on the Sandbox desktop and press Ctrl + V to paste it in.
- Double-click the file inside the Sandbox and watch what it does.
- When you’ve finished, close the Sandbox. Everything in it is deleted, including any malware.
What Is Windows Sandbox?
Windows Sandbox is a small, self-contained virtual machine that’s built into Windows and starts in moments. Once it’s running, you can copy any suspicious files or folders into it.
The Sandbox is kept completely separate from your PC. To paraphrase, “What happens in the Sandbox, stays in the Sandbox.”
Every time you open it, you get a brand new copy of Windows. It can’t see your saved passwords, logins, documents, pictures or anything else on your PC.
When you close it, everything in it is deleted. Everything, including any malware or viruses you might have installed by mistake. The next time you open it, it’s brand new again.
That’s what makes Windows Sandbox so good for testing software.
How to Safely Test Software Using Windows Sandbox
The only way to really find out what a program does is to double-click it and see what happens. That wouldn’t be a good idea on your real computer, but it’s exactly what the Sandbox is for.
Open Windows Sandbox and wait for it to load. It doesn’t usually take long. When it’s running, you need to get the downloaded file into the Sandbox.
Use copy and paste: copy the program, file or folder on your PC (right-click it, then Copy, or select it and press Ctrl + C), then click on the Sandbox desktop and press Ctrl + V.
Drag and drop doesn’t work. You have to use copy and paste.
Share a Folder with Windows Sandbox
Copy and paste is fine for a single download. For bigger files, or a few at once, Windows 11 24H2 and later can share a folder from your PC with the Sandbox while it’s running:
- Click the three dots (…) at the top right of the Windows Sandbox window.
- Choose Share folder.
- Pick the folder on your PC and click Select Folder.
The folder appears on the Sandbox desktop until you close it.
Share an Empty Test Folder, Never Your Documents
A shared folder is the one part of your PC the Sandbox can reach, and anything running in the Sandbox can change the files in it. Make a new folder, call it something like To test, put only the download in it, and share that.
Run the Program Inside the Sandbox
Once the program, file or folder has copied across, double-click it to run it.
In this example, the program is inside a password-protected zip (compressed) folder.
The fact that it’s password protected is your first red flag that something is wrong.
Never open password-protected archives on your real computer. Always copy them to Windows Sandbox and open them there.
Be Very Wary of Password-Protected Archives
There are plenty of genuine reasons for files and folders to have a password, but it’s also a favourite way of spreading malware.
With a password in place, your antivirus can’t look inside the compressed folder until you type the password in. By then, it may be too late.
Programs That Ask You to Restart
Some programs need Windows to restart before they finish installing. Since Windows 11 22H2, that’s fine: restart from inside the Sandbox (click its Start button, then Power, then Restart) and everything in it is still there when it comes back.
Don’t close the Sandbox window to “restart” it. Closing it deletes everything, and you’ll be starting again.
What Happens Next?
What happens next depends on whether the software you’re testing turns out to be genuine.
- If it’s genuine: it installs cleanly and does what you expected, with no surprise pop-ups, extra programs or warnings. That’s a good sign. Close the Sandbox and there’s nothing to uninstall, because everything in it is deleted.
- If something’s wrong: that’s what Windows Sandbox is for. Virus, adware, ransomware, it doesn’t matter. Close the Sandbox and it’s all gone. Then delete the original download from your PC too.
A Clean Test Isn’t a Guarantee
Some malware is clever. It waits a while before doing anything, or it spots that it’s in a sandbox and behaves itself. So before you install anything on your real computer, give it a second check:
- Scan it with Windows Security. Right-click the file on your PC and choose Scan with Microsoft Defender (on Windows 11 you may need to click Show more options first). Here’s how to use Windows Security.
- Check it with VirusTotal. Upload the file to VirusTotal, a free website that checks it with dozens of antivirus programs at once.
- Get it from the official website. If the program has an official site, download it from there instead of a download site.
What Windows Sandbox Won’t Protect You From
Windows Sandbox keeps malware away from your PC, but it can’t stop everything. Watch out for these:
- Your passwords. If a program inside the Sandbox asks you to sign in to your email, bank or any other account, don’t. A fake login page steals your password wherever you type it.
- Files you copy back out. Never copy anything from a program you don’t trust back to your PC. That’s the one way malware can get out.
- Shared folders. Anything in a shared folder can be changed from inside the Sandbox, which is why it should only ever hold the file you’re testing.
- The internet. The Sandbox is online, so anything running in it can reach the internet too. That’s normal, and it’s why you shouldn’t leave a suspicious program running longer than you need to.
Windows Sandbox is just as useful for opening a suspicious email or link safely.
No Windows Sandbox? Free Sandbox Software for Windows Home
Windows Sandbox isn’t available on Windows 11 Home or Windows 10 Home. You can upgrade to Pro, but there are free ways to get the same kind of protection:
A virtual machine. VirtualBox is free and works on Windows Home. It takes longer to set up than Windows Sandbox, and it doesn’t wipe itself, but you can take a snapshot before each test and roll back to it afterwards. Here’s how to set up a Windows 11 virtual machine in VirtualBox.
Sandboxie-Plus. Sandboxie-Plus is free, open-source sandbox software that works on Windows Home. Instead of a separate copy of Windows, it runs a program in a walled-off area of your normal Windows, so it’s quicker to use but less separated from your PC than Windows Sandbox.
Frequently Asked Questions
Q: Is Windows Sandbox free?
A: Yes. It’s built into Windows 11 and 10 Pro, Enterprise and Education, so there’s nothing to buy or download. You just need to turn it on.
Q: Does Windows Sandbox work on Windows 11 Home?
A: No. Home users can set up a free virtual machine in VirtualBox instead, or use free sandbox software such as Sandboxie-Plus.
Q: Can a virus escape from Windows Sandbox?
A: It’s designed so it can’t. The Sandbox runs as a separate virtual machine. The real risks are copying a file back to your PC, sharing the wrong folder, or typing your real passwords into it.
Q: Why can’t I drag and drop files into Windows Sandbox?
A: Drag and drop doesn’t work. Copy the file on your PC, click on the Sandbox desktop and press Ctrl + V. On Windows 11 24H2 and later you can also share a folder from the three-dot menu.
Q: Is anything saved when I close Windows Sandbox?
A: No. Everything in it is deleted when you close it. A restart from inside the Sandbox keeps everything, but closing the window doesn’t.
Q: If a program works in the Sandbox, is it definitely safe?
A: Not definitely. It’s a good sign, but some malware waits or hides when it’s in a sandbox. Scan the file with Windows Security or VirusTotal before you install it on your PC.
Summary
In my opinion, Windows Sandbox is a really important security feature that should be available to every Windows user, whichever edition they have.
It’s such an easy way to get the benefits of a virtual machine, not just for testing software but for opening suspicious files and folders too. Copy it in, try it out, close it, and it’s gone.
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Written by Jeff Porter. I’ve been fixing Windows PCs since 2010 and I’m CompTIA Network+ certified. More about me