Skip to content

Additional security scanners for Windows

If you need Help!

These additional security scanners do not replace your antivirus product such as Windows Defender (Windows 10) or any other certified antivirus. These scanners are strictly a post-infection removal tools. Therefore, we strongly recommend that you use use an up-to-date certified antivirus product.

Microsoft Defender Offline

Microsoft Defender Offline is a built-in Windows 10 component. This feature is a powerful offline scanning tool that runs from a trusted environment, without starting your Windows system. The offline scan runs from outside the normal Windows kernel so it can target malware that attempts to bypass the Windows shell, such as viruses and rootkits that infect or overwrite the master boot record (MBR).

Run Microsoft Defender Offline if :

  • Windows Security detects rootkits or other highly persistent malware on your Windows PC and alerts you to use Microsoft Defender Offline. When it occurs, a message stating that malware was found on your device is displayed, or you receive a message in Windows Security notifying you that additional cleaning is required.
  • You suspect your Windows PC might have malware that is hiding on it, but your security software doesn’t detect anything.

How to run an offline scan ?

Malicious Software Removal Tool (MSRT)

MSRT helps keep Windows computers free from prevalent malware. MSRT finds and removes threats and reverses the changes made by these threats. MSRT is released each month as part of Windows Update and deployed during the CERN monthly patches (must run at least once).

  • Supported Operating System :
    • Windows 11 and 10 (currently supported at CERN), 8.1, 8, 7 (no more supported at CERN).
    • Windows Server 2022, 2019, 2016 (currently supported at CERN), 2012 R2, 2012, 2008 R2, 2008 (no more supported at CERN).

This tool must be run with local administrator privileges.

How to run a scan with MSRT ?

  1. Download MSRT
  2. And perform one of the following actions :
    1. To start the tool immediately after it downloads, click Run.
    2. To save the download to your computer for launch later, click Save.
  3. Open the tool to start scanning.

For more information about Malicious Software Removal Tool.

Microsoft Safety Scanner (MSS)

MSS is a scan tool designed to find and remove malware from Windows computers. Simply download it and run a scan to find malware and try to reverse changes made by identified threats.

  • Supported Operating System :
    • Windows 11 and 10 (currently supported at CERN), 8.1, 8, 7 (no more supported at CERN).
    • Windows Server 2022, 2019, 2016 (currently supported at CERN), 2012 R2, 2012, 2008 R2, 2008 (no more supported at CERN).

This tool must be run with local administrator privileges.

How to run a scan with MSS ?

  1. Download MSS and open it.
  2. Select the type of scan you want run and start the scan.
  3. Review the scan results displayed on screen.
    • For detailed detection results, view the log at %SYSTEMROOT%\debug\msert.log.
  4. To remove this tool, delete the executable file (msert.exe by default).

For more information about Microsoft Safety Scanner.

What are common symptoms of an infection ?

Not all computer performance problems are caused by malicious software.

The presence of malware on your computer may not always be immediately obvious, so it is important to run regular scans. However, some of the more common symptoms are listed below:

  • New toolbars, links or favorites that you did not intentionally add to your web browser.
  • You type the address for a specific site, such as a search engine, but you are taken to a different website without notice.
  • Your Home Page or Search Program in your favorite Internet browser changes unexpectedly.
  • Your files are automatically deleted from your computer.
  • Your computer is turned on Botnet by attackers and it is used to attack other computers.
  • Unattended pop-up ads are displayed without your consent, even if you are not on the Internet.
  • Onscreen Warnings about system infection from a source other than your antivirus software
  • Your Windows machine suddenly starts running more slowly than usual.
  • The Antivirus icon disappears from the system tray or cannot be started.

Where can I get more help with malware and virus infections ?

More about malware and infections