Microsoft quietly includes several built-in security tools inside Windows 11, and one of the most underrated ones is the Malicious Software Removal Tool, better known as MSRT. It’s not a full antivirus program like Microsoft Defender, but it’s designed to specifically remove widespread, high-impact malware—the kind that causes system instability, browser hijacks, weird errors, or slow performance overnight.
If you suspect something malicious slipped through the cracks, MSRT can act like a quick cleanup crew. In this guide, we’ll walk you through exactly how to run it, what each scan type does, where you can find scan results, and how to use the standalone version when needed.
How to Use MSRT on Windows 1
Windows runs MSRT automatically once a month during Patch Tuesday updates, but you can launch it manually any time. Here’s how to use it:
1. Open the Malicious Software Removal Tool
Even though it’s built into Windows, MSRT doesn’t appear in the Start menu like regular apps. We have to launch it through the Run command.
- Press Windows + R on your keyboard to open the Run dialog.
- Type mrt and press Enter.
- When the User Account Control (UAC) prompt appears, click Yes.
This opens the MSRT window, and you’ll see a clean, simple wizard interface that feels like it came straight from Windows XP—but don’t let the look fool you, it still works well.
2. Choose a Scan Type
MSRT gives you three types of scans. Each one performs a different level of inspection:
Quick Scan
This is the default and fastest option. It checks the most common malware locations:
- Windows system folders
- Startup entries
- Key registry paths
If MSRT finds suspicious activity during this scan, it automatically triggers a Full Scan afterward.
Full Scan
This is more thorough and checks your entire system, including all drives.
It takes longer but is useful when you suspect deep-rooted malware or your PC is behaving strangely.
Customized Scan
This option lets you pick a specific folder or drive to inspect. It still performs a Quick Scan before scanning your selected path.
Once you choose your preferred option, click Next to begin the scan.
3. Let MSRT Scan Your PC
This is where the tool gets to work. You’ll see a progress bar along with the current file location being scanned.
Depending on your scanning choice and system hardware:
- A Quick Scan may take 1–5 minutes
- A Full Scan can take 30 minutes to several hours
- A Customized Scan depends on folder size
Feel free to use your PC during the scan, but performance may slow down slightly.
4. Review the Scan Results
After the scan finishes, MSRT shows a summary. You’ll see one of the following messages:
- No malicious software was detected
- Malicious software was successfully removed
- Some malicious software could not be removed
If malware is found, MSRT automatically attempts to quarantine and delete it.
Click View detailed results of the scan if you want to see:
- What malware was detected
- File locations
- Actions taken
- Additional recommendations
5. Open the MSRT Log File (Optional but Useful)
MSRT stores a detailed log every time you run it. This can be helpful if you’re troubleshooting issues or documenting what was removed.
To access the log:
- Press Windows + R.
- Paste this path and press Enter:
%windir%\debug\mrt.log
This opens a Notepad file containing timestamped scan details. If you’re someone who likes keeping your PC clean, this log is helpful to understand what was scanned or removed.
6. Download the Standalone MSRT Version (If Needed)
If you suspect your PC is infected and Windows Update isn’t working, you can manually download MSRT from Microsoft’s site. This version is updated monthly.
- Visit Microsoft’s MSRT download page (search “Microsoft MSRT download” in your browser).
- Choose the version based on your system architecture (usually 64-bit for Windows 11).
- Download the Windows-KB890830 installer.
- Run the tool and follow the same steps as above.
Using the standalone version ensures you’re running the latest malware definitions even if your PC can’t update.
Wrapping Up
The Malicious Software Removal Tool is one of those built-in Windows gems most people forget exists. It won’t replace your antivirus, but when your PC feels off, running MSRT is like calling in a specialist to sweep up dangerous, common malware strains. It works quietly, efficiently, and without adding extra bloatware to your system.
If you’re troubleshooting strange pop-ups, aggressive redirects, or sudden performance drops, running MSRT is always worth a shot before diving into more complex fixes.
