Windows Defender: How to Run a Scan and Check Your PC Is Protected

Windows Defender — now called Windows Security — is a free antivirus and security program that comes built into Windows 10 and Windows 11. You do not need to buy or install anything extra for basic protection. Many people do not realize it is already running quietly in the background, protecting their computer from viruses, malware, and other threats.

Malware is a broad word for harmful software that bad actors try to get onto your computer. This includes viruses (programs that damage your files), ransomware (programs that lock your files and demand payment), and spyware (programs that secretly watch what you type or do). Windows Defender works to block and remove these threats before they cause problems.

Running a manual virus scan every month or two is a good habit, even though Windows Defender runs automatic scans in the background. A manual scan checks every file on your computer and lets you know if anything suspicious is found. Most scans take between 15 minutes and an hour depending on how many files you have.

You should also check that Windows Defender has the latest "definitions" — these are updated lists of known threats. Keeping definitions current means Windows Defender knows about the newest viruses and can block them. Windows updates these automatically, but it is worth checking.

For most people, Windows Defender is more than adequate protection. However, if you frequently download files from the internet, open attachments from unknown senders, or share your computer with others, you might consider adding a complementary tool like Malwarebytes (free version available) for an occasional extra scan.