The tool removes malicious software from an already-infected computer. Antivirus products block malicious software from running on a computer. It is significantly more desirable to block malicious software from running on a computer than to remove it after infection.

Learn how to remove malware from your PC. Use Microsoft Defender Antivirus in Windows 10 or Windows 11 to scan your PC for malware, viruses, or other threats.

If some Windows functions aren't working or Windows crashes, use the System File Checker to scan Windows and restore your files. Though the steps below might look complicated at first glance, just follow them in order, step-by-step, and we’ll try to get you back on track. Run the System File Checker tool (SFC.exe)

Follow these steps to automatically diagnose and repair Windows security problems by turning on UAC, DEP protection, Windows Firewall, and other Windows security options and features. Select the Download button on this page.

Windows Security Update. This update provides latest updates for Windows Security platform, which is comprised of the Windows Security app and its underlying service. To obtain the current version of Windows Security app, please run powershell command below: Get-AppPackage Microsoft.SecHealthUI.

You can start a scan for malware any time you like. Note: Microsoft Defender currently offers anti-malware on Windows, Android, and macOS. From the Microsoft Defender dashboard. If you want a deeper scan, instead of selecting Quick scan in step 3, select Scan options and choose the type of scan you want.

Microsoft is aware of new variants of the class of attack known as speculative execution side-channel vulnerabilities. The variants are named L1 Terminal Fault (L1TF) and Microarchitectural Data Sampling (MDS). An attacker who can successfully exploit L1TF or MDS may be able to read privileged data across trust boundaries.

When a user runs an Office app, such as Word or Excel, diagnostic information is collected and saved to log files on the user’s device. These log files contain information about the processes and components running in the application, and can help detect, diagnose, and fix issues and help make improvements to Office.

Manage your Virus & threat protection settings. Use Virus & threat protection settings when you want to customize your level of protection, send sample files to Microsoft, exclude trusted files and folders from repeated scanning, or temporarily turn off your protection.

Microsoft Defender's real-time anti-malware protection runs whenever your device is on, keeping an eye out for malicious activity. Microsoft Defender will also run quick scans of your device on a daily basis, in case anything manages to elude the real-time protection.