Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsFor most people, malware protection runs automatically, so there is no need to schedule frequent manual scans. Keep one security package active with real-time protection enabled; run a manual full scan when you have a specific reason to suspect malware or want an occasional check. Ask Leo! describes scanning about once a month as an option, not a requirement.
What happens without a manual scan?
Security software generally handles routine monitoring for you. Ask Leo! says most security software runs automated scans at least daily, while real-time protection can check common activity such as downloads and newly installed software. The practical first step is to confirm your installed security package is active and its real-time protection is on.
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On Windows 10 and Windows 11, the example in Ask Leo! is Windows Defender, now surfaced through Windows Security. Installing another security package can turn off Defender, so check which product is currently providing protection rather than assuming both are active. Avoid running multiple packages with real-time scanning enabled.
Free tools Windows power users keep installed
One-click scans. No signup required.
When should you run a manual scan?
If you suspect malware
Run a manual full scan if something has made you suspect malware or you believe routine protection may have missed it. A full scan takes longer than a quick scan. In the described Windows example, it scans fixed internal drives; external removable drives and network-connected drives are not included.
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If you want an occasional check
A monthly full scan is a reasonable optional interval if it gives you peace of mind, but it is not a universal rule. Ask Leo! author Leo A. Notenboom says he rarely, if ever, runs one himself. The recommendation is practical advice, not a claim based on a controlled comparison of scan schedules.
What if the scan is clean but you remain concerned?
A clean result does not prove that no malware is present. If you still have a concrete reason for concern, an additional scan with a second tool can provide another opinion. Ask Leo! mentions Malwarebytes as an example, but a second scan is not a guarantee that everything will be found. Check whether installing another security package changes the real-time protection state of your primary one.
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Quick decision guide
- No specific warning signs: Keep your security software and real-time protection active; frequent manual scans are generally unnecessary.
- You want reassurance: Run an occasional full scan; monthly is one optional cadence, not a requirement.
- You suspect an infection: Run a full scan, and consider a second-opinion scan if concern remains despite a clean result.
- You installed another security package: Verify which package is active and that real-time protection is enabled.
Source: Ask Leo!, “How Often Should I Scan My Computer for Malware?”, associated with the September 1, 2026 Confident Computing issue.
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