Microsoft Defender Antivirus is a powerful tool that finds and removes malware from your PC. Here's how to use it in Windows 10 or 11 to scan your PC. Important: Before you use Microsoft Defender Offline, make sure to save any open files and close apps and programs. Open your Windows Security settings.

Use this tool to find and remove specific prevalent threats and reverse the changes that they made (see the "Covered malware families" list in the "Release information" section of KB 890830 ). For comprehensive malware detection and removal, consider using Windows Defender Offline or Microsoft Safety Scanner.

Each release of the tool helps detect and remove current, prevalent malicious software. This malicious software includes viruses, worms, and Trojan horses. Microsoft uses several metrics to determine the prevalence of a malicious software family and the damage that can be associated with it.

Solve problems with detecting and removing malware with Windows Security, including incomplete scans, detection errors, and persistent malware.

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.

Explains how to download the latest antimalware definition updates for Microsoft Forefront Client Security, Microsoft Forefront Endpoint Protection 2010 or Microsoft System Center 2012 Endpoint Protection without installing Microsoft Windows Server Update Services (WSUS).

Your PC isn't working well and you recently installed an app. Restore from a system restore point. You suspect your device has been infected. Use installation media to reinstall Windows 11. Select one of the recovery options below and follow the steps to try to get things working again.

Tamper Protection in Windows Security helps prevent malicious apps from changing important Microsoft Defender Antivirus settings, including real-time protection and cloud-delivered protection. If Tamper Protection is turned on and you're an administrator on your computer, you can still change these settings in the Windows Security app.

If you cannot open your Outlook data file or suspect that the file is damaged, use the Inbox Repair tool (scanpst.exe) to repair errors in the file.

Windows 11 Windows 10. Find your Windows settings in a snap! Select the Start button, then select Settings . From there, browse the categories or use search to find what you're looking for. Windows 11 Windows 10. Tips: Most apps have their own settings. In the app, select Settings to make app-specific changes.