Windows Defender, the built in antivirus solution in Windows 10, is fairly good. While Windows Defender is no match to popular antivirus software from Kaspersky, Bitdefender or ESET, it’s definitely offers basic security on PCs where there is no third-party antivirus software is installed.
Not all malicious and potentially unwanted software can be removed when Windows is running as they load with Windows operating system. Because of this reason, many popular antivirus programs request the user restart Windows to completely remove the detected malicious code.
To help users, many antivirus developers provide an offline version of their antivirus software so that users can scan their PC and remove threats that cannot be removed otherwise using the standard method.
As you likely know, Microsoft has also been offering Windows Defender Offline Tool for years to help users remove malware and other potentially unwanted programs from Windows PC without having to boot into Windows.
Windows Defender offline scan feature in Windows 10
Before this, Windows 10 users had to download and use the Windows Defender Offline Tool from Microsoft and then prepare bootable USB/CD of it in order to perform an offline scan. You no longer need to download and prepare Windows Defender Offline Tool as Microsoft has added offline scanning capability to Windows Defender and users running Windows 10 build 14271 (check your Windows 10 build number) and later can use this feature to perform Windows Defender Offline scan without downloading the tool.
According to Microsoft, on Windows 10, Windows Defender Offline feature is completely automated. This means that, whenever Windows Defender comes across a hard to remove malicious code, it will alert the user to run the Defender Offline scan.
How to run and use Windows Defender offline scan feature in Windows 10
Step 1: Open Settings app by either clicking Settings in left-side of the Start menu or simultaneously pressing Windows logo and I keys.
Step 2: In the Settings app, click Update & Security.
Step 3: Click Windows Defender.
Step 4: Finally scroll down the page to see Windows Defender Offline section. Click the button labelled Scan Offline to restart your PC.
You will see “your PC will be restarted in a minute” message.
Step 5: During the restart, you will see the following Windows Defender Offline loading screen before you see the Windows Defender screen.
The Windows Defender will automatically start scanning your PC and will remove malicious and unwanted programs that Defender can’t remove otherwise.
If Windows Defender antivirus definitions are not up to date, you can switch to the Update tab and then click Update button. Note that you might get “Virus and spyware definitions couldn’t be updated” error if you are using Wi-Fi. When we tried updating definitions after connecting an Ethernet cable on your test machine, definitions were updated without any issues.
The Defender might take up to 20 minutes to complete its job. And Windows Defender’s offline scan is done, your will see the lock screen.