Step-by-Step How-To · 5 min read
How to Check a File or Download for Malware
If you are unsure about a file you downloaded, check it before opening it. Three simple methods cover almost every case.
Published 2026-08-09 · Last updated 2026-08-09
Right-click and scan locally
On Windows, right-click the file and choose Scan with Microsoft Defender (or your installed antivirus). This runs the same engine that protects you in real time, but on demand and immediately.
Use a multi-engine online scanner
Services such as VirusTotal run a file against dozens of engines at once and show which ones object. Two important caveats: uploaded files may be shared with security vendors, so never upload anything containing personal or confidential data, and a couple of low-profile engines flagging a file is often a false positive rather than proof.
Verify the publisher and the hash
Right-click → Properties → Digital Signatures shows who signed an installer. A missing or mismatched signature on software from a major vendor is a serious warning. Where the developer publishes a SHA-256 hash, compare it using Get-FileHash in PowerShell.
When in doubt, do not open it
No scan is conclusive for a brand-new sample. If the file arrived unexpectedly, came from a search advertisement rather than the official site, or asks you to disable your antivirus to install it, delete it.
Frequently asked questions
- Is there a free file virus scanner?
- Yes — your installed antivirus scans on demand for free, and multi-engine web services offer free file checks within size limits.
- Does one engine flagging a file mean it is malware?
- Not necessarily. Single detections from minor engines are frequently false positives. Weigh the source and the publisher signature too.