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What’s the Difference between Microsoft Security Essentials and Windows Defender?

I use Windows Defender Offline on a flash drive both at home and at work. On the computers themselves, however, the screen sometimes says Microsoft Security Essentials and other times, it says Windows Defender. I forgot to check if the Windows Defender has Microsoft Security Essentials installed. Does it really matter which one shows up?

Microsoft’s product naming frustrates me to no end. They seem to have an incredible knack for picking the most confusing names possible.

While the names Microsoft Security Essentials and Windows Defender seem innocuous enough, what they mean has changed over time. And therein lies the confusion.

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Microsoft Security Essentials

Let’s start with the easy one – this name has remained relatively unambiguous over time.

Microsoft Security Essentials (MSE) is an all-in-one anti-virus and anti-spyware program. It’s a free download from Microsoft and integrates well with Windows XP, Vista, and 7.

In fact, it’s one of my recommended anti-malware solutions, if you’re running those operating systems.

Windows Defender

This is where things get weird.

Windows Defender Windows Defender was originally an anti-spyware tool only. In those days, you needed to also install an anti-virus tool. MSE was one such solution, but because it included an anti-spyware tool, it replaced Windows Defender.

Today, however, Windows Defender is the new name for the version of  Microsoft Security Essentials that comes pre-installed on Windows 8.

So today, Windows Defender and Microsoft Security Essentials are essentially the same thing (so to speak). The difference is which version of Windows that they apply to and how you get them: Windows Defender is pre-installed in Windows 8 and Microsoft Security Essentials is a free download from Microsoft…  unless you’re talking about Windows Defender Offline. That’s something else entirely different.

Windows Defender Offline

Windows Defender Offline is a version of Windows Defender that you burn to a CD or install to a USB thumb drive. You can then boot from that CD or drive and run Windows Defender without having to actually run the copy of Windows that’s installed on your machine.

More importantly, by booting from something other than your hard drive, it bypasses any of the malware that might be on your machine. The result is that Windows Defender can do a more complete job of cleaning things up.

Windows Defender Offline is a free download from Microsoft. The download walks you through the steps to create the CD or USB thumb drive.

Oh, and to complete the whole naming saga: Windows Defender Offline was originally called Microsoft Standalone System Sweeper.

Posted: November 11, 2013 in: Security Software
This is an update to an article originally posted April 6, 2012
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12 comments on “What’s the Difference between Microsoft Security Essentials and Windows Defender?”

  1. There may be some additional confusion as to what the asker is referring to, courtesy of Microsoft. About a year ago (or more) Microsoft released a Beta tool called Microsoft Standalone System Sweeper. People just called it “Microsoft Sweeper”. A few months later it was renamed Windows Defender Offline Beta. Either name, the tool was/is a free, standalone, bootable malware and virus remover. Neither MSSS nor the renamed WDO have anything to do with either MSE or the old antispyware that was called Windows Defender. I think 🙁

  2. I always believed that Windows before 8 did not come with Antivirus, because I thought it would violate some sort of antitrust laws. I would think that the Mcafees and Nortons would sue Microsoft, like they got sued over bundling Internet explorer with Windows 95. When I bought this thing Windows defender was already turned off, so the free trial of Norton could be run. After that, I am using the free trial of Trend Micro, that Best Buy gave me on CD. When that one runs out in 83 days, I will uninstall it and turn on windows Defender/MSE for Windows 8. I am just used to MSE/Windows Defender. The interface looks alike. The last time I bought Antivirus was around 2002, and ten avira free came out, followed by MSE.

  3. Dude,,,you should have mentioned the History of this Anti-malware…..
    It is basically Microsoft AntiSpyware then Windows Defender, then it became Microsoft OneCare then Windows Live OneCare then Microsoft Security Essentials then it reverted back to it’s original name which is Windows Defender,,,but then they are all entirely the same engine…..just updated.

  4. I may not be the brightest bulb in the pack! The reason I say that is, I’ve been using windows since 1998. Way back when they had dial up. 🙂 I learned early on that all the anti virus, and anti malware, slows my old computers to “almost a standstill”. So seeing how I consider myself a nobody on the internet, I don’t secure any site I may be on, for the simple reason! I never buy anything online. All my computers run super fast. True I have upgraded over the years, but I still use the least amount of security I can implement. P.S. I never been hacked.

  5. I found MSE not able to handle malware such as WhiteSmoke, Conduit, Datamngr, and DomaIQ and many of the Fake FBI (ransomware). No one protection program has all the answers but just lately I was able to fix all of the above with RKill, Malwarebytes Anti-Malware, and to get the difficult web links and back connections I found Hitman Pro Kickstart (30 Day trial) to finish it off. A cool trick is to insert RKill into your Start Up folder and reboot. Give it about 2-3 minutes and you can get around without the FBI screen locking this up.

  6. My Windows 7 64 bit OS came with Defender installed. Is this unusual? I thought Defender was only installed on Windows 8.
    Currently I have Defender turned off, and MSE installed from the Microsoft website.

    • I saw the same thing on a new Win 7 machine I got today, but it was Miscrsoft Security Essential installed, not Defender. Same program, different name. It must be that they included it in an update.


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