Windows defender is a free built-in antimalware and antivirus from Microsoft for Windows 8 and Windows 10. Windows Defender is a very good tool which helps your Windows to keep safe from malware and viruses.
As antivirus upgrade, hackers upgrades too and change their ways to hack. Which means no antivirus is perfect and your Windows might be affected by some viruses or malware. Some advanced malware or viruses can embed to your Windows files and infect the core features.
In this situation, you need to scan your whole Windows but scanning with installed antivirus won’t help you because it will be infected too and won’t detect anything. Then you have to plug your hard drive to other computer and perform scanning. Or use an offline tool to scan your system.
Offline scanning means antivirus to scan your PC outside the operating system. To do this you need a boot disk by antivirus developers to scan offline. The boot disk will boot-up as your Windows boot and scan your whole Windows and delete the infected files and apps. Instead of buying boot disk, Microsoft Windows defender offers this option built-in to scan your Windows offline.
Why Windows Defender Offline Scan?
- You must run Defender Offline scan when Windows security found something that can’t be fixed without Defender Offline. Windows might alert you that malware was found on your device or some security notification like additional cleaning is required.
- When you might suspect your computer has some hidden highly persistent malware and your security software isn’t capable to detect it. For peace of mind, you should give a try and use Windows Defender Offline scan tool as guided below.
How to perform Windows Defender Offline scan
- First, open “Windows Defender”. Press Windows key from the keyboard, start typing Defender and hit Enter.
- Once Windows Defender windows (Windows Security) appear, then select Virus & threat protection from the left side menu list.
- To open off the scanner, simply click on scan option under the Quick scan button.
- Here select the last radio option Windows Defender Offline scan.
Some malicious software can be particularly difficult to remove from your device. Windows Defender Offline can help to find and remove them using up-to-date threat definitions. This will restart your device and will take about 15 minutes.
- Now click on Scan Now button and windows will show save your work. Windows Defender offline scan will take some time and restart your device save all work before continuing.
- After a few times, your windows will restart and boot up with windows defender to scan your PC offline.
Just leave the system and sit back. It will scan your whole PC and delete all the infected files and apps from your computer. After everything’s done your computer will again restart and boot to normal windows.

Note: in any case, you just need to back up your data, after scanning it might be deleted one of your important application or file.