Anyone have any experience with Windows Defender? Is it a replacement for antivirus software or something else to run alongside?

We are looking for something that isnt as bloated as McAfee 8.5i.

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    Any chance anyone wants to provide an updated answer with experience in June 2013 or later?
    – qxotk
    Commented Jul 22, 2013 at 23:21

9 Answers 9


I've yet to see any use for Windows Defender, in my limited exposure to it, other than to alert me that there wasn't any recent updates on the system. The security control panel is often more talkative than the windows update system.

Personally I've always used Kaspersky Anti virus. They do have an "internet security suite", but considering the additional resources it uses over the "anti virus" option, I go for the AV. It's very fast, updates every 2-4 hours (although you may set this option to anything you'd like), and I've used it time and time again to pull infected windows installs from the dead.

Just a happy user of it, although I'm primarily a Linux user at home, I do support 40+ Windows workstations, and all of them are well protected with Kaspersky.


Defender is just an anti-spyware kit. It's not going to stop all viruses so you'll still depend on a decent virusscanner. But it can replace some of the McAfee features.

  • Looks like in Windows 8 Defender is much better, and can be used as a eal antivirus. pcworld.com/article/2020260/…
    – Omiod
    Commented Jan 21, 2013 at 16:45
  • True, but the original question is almost 4 years old. Still, I would not use just Windows Defender and no other antivirus product. I myself still use McAfee in my Windows 8 boxes. Microsoft provides it so users of Windows 8 have at least some minimal antivirus protection, since Windows tends to be one of the most popular platforms for malware. (But Android is starting to compete for that title.) Commented Jan 22, 2013 at 17:44

Windows Defender is old.

Check out Microsoft Security Essentials, which "provides real-time protection for your home PC that guards against viruses, spyware, and other malicious software. ". MSE came out in mid-2009. It's free for licensed Windows installations.

Consumer Reports rated Anti-malware program in their latest issue, and Microsoft Security Essentials is one of the top free contenders. The report is available in the June 2010 issue, article "Security software" (still on the stands now), or via a paid subscription to www.consumerreports.org.

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    I use MSE on my personal laptops. Seems to be doing a good job of not bugging me and keeping me and my (non-technical) family safe.
    – Gomibushi
    Commented May 19, 2010 at 20:55
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    MSE is an AV + malware replacement for defender. installing it disables defender as part of the install process Commented Jun 3, 2010 at 4:00

Windows Defender is an anti-spyware program, not an antivirus program. You still need a separate antivirus program. Some computer security suites include antispyware programs, and so you may be able to uninstall (on Windows XP) or turn off (on Vista) the Windows Defender functionality if you have this threat covered in another way.

I have McAfee VirusScan on approximately 90 machines, and I know first-hand that it can, indeed, slow your computer down, but you can configure it at a very fine level of granularity. As always, performance and security involve trade-offs. The more things you want VirusScan or any other antivirus program to check, the more processor and memory resources it will use.


Hmmm, any anti-virus that is any good should hook in any access/execution made on the system for a already known signature or common exploit type. This also means that any good anti-virus will slow your processes down dramatically.

I would rather go to a different approach, disallow changes/installations outside the users directory except for approved binaries. Have the users directory in a DFS and make regular backups. Scan incoming network on know pests.

I used this method in the past in a 4k+ users network and it worked fine, but I also think I was very lucky to never had a major pest problem in the last 8 years.


I'm of the opinion that it's more suitable for home users or really small workgroup-level networks. If you're scanning all inbound (and outbound - it's your responsibility to ensure that something nasty doesn't get out of your network and on to someone else) traffic at the gateway level, have a decent corporate AV solution in place, and have implemented sensible desktop-level security precautions and web access control/filtering, then I don't really think you need it.

Of course, it is an extra layer of protection so it may give you a greater comfort zone, but one thing it is not is a replacement AV solution.


Based on conversations that I have listened to on Security Now, Windows Defender is an anti-spyware software that scans your system for known threats. It does not do any real-time scanning as many anti-virus programs do and its definition files are updated by the monthly Microsoft update. Incidentally, that is when the program is also run. I would suggest that you keep it on your system, enabled, and updated as well as run a good anti-virus program. Here is some information from Microsoft about it.


I have Windows Defender, which from the above conversations, sounds like an anti-spyware only product. I use it side-by-side with Panda Antivirus (free). It works flawlessly, for now at least. I'm pretty happy with it.


My assessment is you will definitely be protected for the price for slowed computer.

so if you can maximize the computer unit speed it a very bad thing. I've been experiencing this issue for a week i knew i disabled windows defender but for installing software and update is return back and cause me working time drastically.

so my assessment is its pretty bad from my experience.

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