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Microsoft security software

Microsoft has a range of security software to help protect your computer from malware and potentially unwanted software. This page has answers to common questions about our products.

You can get more help on the following pages:

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What are the Microsoft security products?

You can learn more about our full range of security software on our product page:

There is more information about our protection and the benefits available for Microsoft customers on our Customer protection page.

How can I update my Microsoft security software?

You find the latest updates for your Microsoft security software on our product page:

New malware threats are created and detected every day. This is why it is essential to keep your security software up-to-date.

What should I do if my security software detects a threat?

Your Microsoft security software will tell you when it removes a threat. When this happens you don’t need to do anything else.

If potentially unwanted software has been found on your computer you may be asked to choose what to do next. When this happens you will see a message in the bottom corner of your screen.

When you see this message you can choose to either click Clean computer or Show details.

If you choose Clean computer the file is removed.

The Show details button lets you choose to either remove, quarantine or allow the file.

Every threat is given an alert level to help you decide what to do.

Should I remove, quarantine or allow a threat?

Not all files detected by your Microsoft security software would be considered unwanted by all people (hence we use the term 'potentially unwanted' to describe some programs). For programs like these you are asked to choose what you would like to do.

  • Remove deletes the file from your computer.

  • Quarantine moves the file to a new location and blocks it so that it can't run.

  • Allow adds the file to an allowed list and lets it run on your computer.

If you allow a file you won’t get any more alerts about it. Only allow a file if you trust the software and the software publisher.

A threat’s alert level can also help you decide what to do.

Where can I get more information about a threat?

The Microsoft Malware Protection Center Encyclopedia has more information about all of the threats we detect.

How can I review a quarantined file?

To review your quarantined files:

  1. Open Microsoft Security Essentials or Windows Defender

  2. Click the History tab

  3. Select Quarantined items and then View details. You might be asked for an admin password or to confirm your choice.

Once you have reviewed the quarantined items you can either:

  • Select Remove all to get rid of all quarantined software

  • Select individual files, and then choose either Remove or Restore

Most files detected by Microsoft security software are quarantined. This means the file is moved and stopped from running or doing anything to your computer.

A quarantined file does not pose any risk to your computer. You can leave a file in quarantine for as long as you like.

What do the alert levels in my security software mean?

Alert levels help you choose what to do when potentially unwanted software is found on your computer.

Microsoft uses four alert levels:

  • Severe – widespread or highly dangerous malware that can affect your privacy and damage your computer

  • High – programs that can collect your personal information or make changes to your system

  • Medium –programs that might affect your privacy or change the way your computer behaves

  • Low - potentially unwanted software that might collect information about you or your computer or change how your computer works

Alert levels help you understand how dangerous a threat could be and decide what to do next.

You can find out more about each alert level in the following article:

What are definitions?

A definition is code that is used by your security software to identify threats.

Definitions are also knows as signatures, DAT files, pattern files, identity files, and antivirus databases.

How do I know if I have a 64-bit or 32-bit operating system?

  1. Open the Start menu or Start screen, type Computer, and press Enter.

  2. Right click or tap and hold Computer in the left side of the Window and choose Properties.

  3. Your version type will be shown under “System type” in the “System” section

The following page has more information:

How to determine whether a computer is running a 32-bit version or 64-bit version of the Windows operating system

I can’t update my security software

The following page can help you find answers to the most common issues and error codes:

If you can’t update your security software there may be a problem with your computer.

Where can I get help?

You can find answers to common issues and questions at the Microsoft Community Virus and Malware website.

If you think your computer is infected you can also get help at the links below:

If you suspect a file includes malware or potentially unwanted software you can submit it to us for analysis.