What do Windows Defender warnings mean?

Windows Defender is a Microsoft program that helps protect you against spyware and other unwanted software. It’s built into Windows Vista and you can download it for free if you use Windows XP.


Windows Defender provides real-time protection, but also allows you to scan your computer for spyware manually. If it finds anything suspicious you’ll see an alert.


Here’s what the alerts mean and what you should do about them.


Alert level

What it means

What to do


Widespread or exceptionally malicious programs, similar to viruses or worms, which negatively affect your privacy and the security of your computer, and can damage your computer.

Remove this software immediately.


Programs that might collect your personal information and negatively affect your privacy or damage your computer, for example, by collecting information or changing settings, typically without your knowledge or consent.

Remove this software immediately.


Programs that might affect your privacy or make changes to your computer that could negatively affect your computing experience, for example, by collecting personal information or changing settings.

Review the alert details to see why the software was detected. If you do not like how the software operates or if you do not recognize and trust the publisher, consider blocking or removing the software.


Potentially unwanted software that might collect information about you or your computer or change how your computer works, but is operating in agreement with licensing terms displayed when you installed the software.

This software is typically benign when it runs on your computer, unless it was installed without your knowledge. If you’re not sure whether to allow it, review the alert details or check to see if you recognize and trust the publisher of the software.

Not yet classified

Programs that are typically benign unless they are installed on your computer without your knowledge.

If you recognize and trust the software, allow it to run. If you do not recognize the software or the publisher, review the alert details to decide how to take action. If you’re a SpyNet community member, check the community ratings to see if other users trust the software.


About the Author
Eve Blakemore

Group Manager, Trustworthy Computing

Eve Blakemore is a Group Manager for Trustworthy Computing who delivers consumer guidance around the latest trends in security and privacy. Eve joined Microsoft in 1998 and has worked in corporate and field roles with Microsoft Learning, US Public Sector, Read more »

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  1. sqloogle

    I have lot of issues with Windows Defender, even though I set it to schedule the scan on every evening 19:00 hours it doesn’;t run. What could be the probleM?

  2. Marcelle Amelia

    I’m not sure what your exact problem is, but you can contact the Microsoft support to get more help. As a Windows Defender user you get 2 support requests at no charge.

    You can find general support information on Windows Defender at http://support.microsoft.com/ph/11952/en-us/ .  

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