Young man sitting in a green chair and smiling at the camera

Learn about threats

Explore our in-depth threat encyclopedia for information about threat types and specific malware

Learn more
Man using a notebook computer

Get updates

Download the latest definitions for your antimalware product.

Download updates
Two women using a Macbook together

Submit file for analysis

Ask our analysts to check suspected malware or incorrectly detected files.

Submit files

Latest news

VIEW ALL
  • Windows Defender Antivirus

    Enable Windows Defender Antivirus

    Keep your PC safer with the free, trusted antivirus protection built in to Windows 10.

    MORE
  • Windows Defender Advanced Threat Protection

    Sign up for Windows Defender ATP

    Detect, investigate, and respond to targeted attacks in the enterprise using cloud-based behavioral analytics.

    MORE
  • Microsoft security software

    Get Microsoft Security Software

    Stay protected with the right security software that work effectively with Windows.

    MORE
  • Sources of infection

    Understand sources of infection

    Learn how malware typically infect computers and how to mitigate the risks.

    MORE
  • Troubleshooting for infection

    Troubleshoot for infection

    Learn how to check your computer for possible infection.

    MORE
  • Windows Defender Security Intelligence help center

    Visit the help center

    Explore our collection of helpful security advice to keep your computers safe.

    MORE

Community discussions

Windows Defender keeps turning off

Scanning, Detecting, and Removing Threats

Windows Defender Full Scan Fails (After Creators Update)

Scanning, Detecting, and Removing Threats

Malware asked me to call a number

Scanning, Detecting, and Removing Threats

Virus scan of a file

Scanning, Detecting, and Removing Threats

Scan doesn't start/stuck

Scanning, Detecting, and Removing Threats

Windows Defender: virus and spyware definitions are not updating

Updating Virus and Spyware Definitions

VIEW ALL