Microsoft Defender Antivirus is built into Windows and normally runs in the background. You can also start scans manually when something feels suspicious or you want to check a specific file.
This applies to Windows 10 and Windows 11 when Microsoft Defender is the active antivirus.
Does This Affect You?
Use Quick scan for routine checks, Full scan for a deeper review, and Microsoft Defender Offline when malware may be hiding while Windows is running.
Run a Quick Scan
- Search for Windows Security and open it.
- Click Virus & threat protection.
- Click Quick scan.
- Wait for the scan to finish.
- Review the result and quarantine or remove anything Defender finds.
Run a Full Scan
- Open Windows Security > Virus & threat protection.
- Click Scan options.
- Choose Full scan.
- Click Scan now.
- Let it finish. It can take from 30 minutes to several hours depending on storage size.
Run Microsoft Defender Offline
- Open Scan options.
- Choose Microsoft Defender Offline scan.
- Click Scan now.
- Save your work because the PC will restart.
- Defender scans from a separate environment, then restarts back into Windows with results.
More Defender Scan Options
Scan One File or Folder
Right-click a file or folder in File Explorer and choose Scan with Microsoft Defender.
Schedule Recurring Scans
Open Task Scheduler, browse to Task Scheduler Library > Microsoft > Windows > Windows Defender, and adjust the Windows Defender Scheduled Scan trigger.
Check Real-Time Protection
Open Defender settings and confirm Real-time protection is on. If another antivirus is installed, Windows may disable Defender’s active protection automatically.
Sources
- Microsoft Support: Stay protected with Windows Security
- Microsoft Support: Run a scan using Microsoft Defender Antivirus
- Microsoft Learn: Microsoft Defender Offline