How to Use Microsoft Safety Scanner in Windows

Microsoft Safety Scanner is a free, on-demand virus and malware removal tool from Microsoft. Unlike Microsoft Defender Antivirus, it does not run in the background or provide real-time protection. Instead, you download and run it when you suspect your PC is infected, then it scans and removes threats. This guide walks you through the entire process, from downloading to interpreting results, and covers common pitfalls and fixes.

What You’ll Need

• A Windows PC (Windows 11, 10, 8.1, or 7) with an internet connection.
• Administrator privileges to run the tool.
• About 1–2 GB of free disk space (the tool is ~100 MB, but scan files can grow).
• At least 30–60 minutes of uninterrupted time for a full scan.

Step-by-Step

1. Download the tool. Go to the official Microsoft Safety Scanner download page (search “Microsoft Safety Scanner download” and look for the microsoft.com link). Click Download and choose the version that matches your Windows architecture (64-bit or 32-bit). You can check your architecture in Settings > System > About (under “System type”).
2. Save the file to a convenient location. Choose your Downloads folder or Desktop. Do not run it from a network drive or a USB stick unless you have to—local is faster.
3. Right-click the downloaded file and select “Run as administrator.” If prompted by User Account Control (UAC), click Yes. This gives the tool the permissions it needs to scan deeply.
4. Accept the license terms. Read the agreement, check the box, then click Next.
5. Choose the scan type. You have three options:
   • Quick scan – checks the most common infection points (fast, good for a first pass).
   • Full scan – checks all files and running programs (can take hours, but thorough).
   • Custom scan – lets you pick specific folders or drives (useful if you know where the problem is).

   For a suspected infection, start with Full scan. If you’re short on time, run Quick scan first, then follow with a Full scan later.

6. Click Next to start the scan. The tool will show a progress bar. You can continue using your PC, but it’s best to avoid heavy tasks (like gaming or video editing) to speed things up.
7. Wait for the scan to complete. When done, you’ll see a summary of threats found and removed. If nothing is found, you’ll see “No threats detected.”
8. Click Finish to close the tool. The tool does not leave any background processes, so you’re done.
9. Restart your computer if the tool removed any threats. This ensures all malicious files are fully cleared.
10. Delete the downloaded file (or keep it for a few days). The tool is valid for about 10 days after download, so if you need to re-scan later, download a fresh copy.

Common Mistakes

• Running the wrong architecture. Downloading the 32-bit version on a 64-bit system can cause errors. Always check your system type first.
• Not running as administrator. Without admin rights, the tool may fail to scan certain areas or simply won’t start.
• Using an outdated version. The tool expires after ~10 days. If you’ve had it on your desktop for a month, it won’t work. Always download a fresh copy each time.
• Confusing it with real-time protection. Safety Scanner is a one-time scan. It does not protect you after it closes. You still need Microsoft Defender or another antivirus running.
• Interrupting the scan. Closing the window or shutting down mid-scan can leave partial removals. Let it finish.

Tips

• Run Safety Scanner in Safe Mode if your PC is badly infected and the scan keeps failing or crashing. To enter Safe Mode, restart and press F8 (or use Settings > Recovery > Advanced Startup).
• Before scanning, disconnect from the internet if you suspect a network-borne infection. This can prevent malware from downloading more payloads while you scan.
• Use Custom scan to target a specific USB drive or folder if you don’t have time for a full scan.
• After the scan, update Windows and your antivirus to patch vulnerabilities that allowed the infection.
• If you have a second antivirus installed, temporarily disable it during the scan to avoid conflicts.

Troubleshooting

• Tool won’t start or crashes immediately. Try downloading the file again (it may be corrupted). Also, check that your Windows is up to date. If it still fails, run it in Safe Mode.
• Scan gets stuck at a certain percentage. Give it 15–20 minutes. If it doesn’t move, restart your PC and run a Quick scan first, then a Full scan later.
• Error message about “This app can’t run on your PC.” You’ve likely downloaded the wrong architecture. Re-download the correct version.
• Tool says “No threats found” but you still have symptoms. Run a Full scan (if you only did Quick), or try Microsoft Defender Offline (built into Windows) which scans before Windows starts.
• Threats are found but can’t be removed. Some malware is stubborn. Try running the scan in Safe Mode, or use the “Custom scan” to target the specific file location. If that fails, consider a Windows reset or professional help.

Frequently Asked Questions

Is Microsoft Safety Scanner the same as Microsoft Defender?

No. Microsoft Defender is your always-on antivirus that provides real-time protection. Safety Scanner is a separate, on-demand tool that you run manually to remove existing threats. They complement each other.

How long does a full scan take?

It varies widely—anywhere from 30 minutes to several hours, depending on your hard drive size, speed, and how many files you have. A Quick scan usually takes 5–15 minutes.

Can I use Safety Scanner on a server?

Yes, Microsoft Safety Scanner works on Windows Server versions as well, provided you have the right architecture and admin rights.

Does Safety Scanner replace my antivirus?

No. It’s a one-time scanner, not a real-time protector. You must keep a dedicated antivirus (like Microsoft Defender) active.

Why does the tool expire after 10 days?

Microsoft updates the tool’s definitions daily, so the version you download becomes outdated quickly. Expiring forces you to get the latest definitions, ensuring better detection.

Can I run Safety Scanner while my antivirus is running?

Yes, but it’s best to temporarily disable other security software to avoid conflicts and speed up the scan. Just remember to re-enable it afterward.

Related

• How to Set Up a Wireless Printer on Windows 10
• PS2SV App Choices, Setup & Backup Codes
• How to Export Facebook Messages