I am looking for a free antivirus app which supports manual scanner only mode. It should NOT turn off the Microsoft Defender app.

So far, I tried avast. The bad part to me is it turns off Microsoft Defender after its installation and I found no way to enable Microsoft Defender again.

I want Microsoft Defender to do the monitoring task and another free antivirus app to handle manual virus scanner task, so that I can scan files with another antivirus app manually than the Microsoft Defender.

Hopefully, I made myself clear on this.

Thank you very much.

  • I never heard that an antivirus cannot work with Windows Defender on. Maybe you are talking about some file that needs to be whitelisted by Windows Defender? Dec 22, 2021 at 9:30
  • @FrancescoMantovani Sorry, no, I don't mean some file that needs to be ... The only antivirus app that I tried is avast. If you install avast, Windows Defender will be turned off automatically. I tried to turn it on with no luck on the latest avast one software in windows 11. Which free antivirus app did you use that supports windows defender on? Are you sure windows defender is actually on all the time? By checking windows 11 setup, only one antivirus protection can be on at a time. You can not choose more than one virus protection in WIndows 11 Settings.
    – sgon00
    Dec 22, 2021 at 9:39

2 Answers 2


I use Clamwin for this.

It runs on Windows but is purely manual. It will only scan a file when you tell it to. It does not scan files on access in real time, you can leave that to Defender if you wish.

It is free to use.

  • Thank you very much for your answer. It's even open source in github. My favorite option is open source. I have upvoted your answer and will accept it soon if there is no other better answer. Cheers.
    – sgon00
    Dec 22, 2021 at 9:42
  • In general I agree that open source is preferred. Unfortunately when it comes to virus detection maintaining the virus detection patterns is quite some work and as far as I remember ClamAV always is not very good in comparisons to other anti virus software when it comes to detection rate.
    – Robert
    Dec 22, 2021 at 20:49
  • @Robert yeah, I agree. From my testing, Clamwin/CLamAV can not uncompress and scan files inside compressed files and it took a much longer time on scanning too. For instance, I tried to scan an app installation folder which contains zip files. Microsoft Defender scanned 17849 files in 1 minute. But Clamwin/ClamAV only scanned 75 files in about 4 minutes. So Clamwin is not really a good option here.
    – sgon00
    Dec 23, 2021 at 4:02

For scanning single files I would recommend to not rely on a single virus scanner. Instead you can upload them to https://virustotal.com which shows you the scan result of all major and common virus scanner.

VirusTotal also displays other valuable information like when was a file first seen and other details from the file analysis.

There is also a software for Windows which integrates itself into the send to menu for uploading files to Virustotal pretty easy (the upload is only done if the digest of the file is unknown to VirusTotal). Unfortunately support for this tool is stopped but it is still available on their site. It still works on Windows 10. Besides the send to menu integration this tool does not change anything in Windows so Defender will remain active.

  • Thank you very much for this answer. But I don't think uploading files for scanning is an option to me. I have two concerns. (1) The size of files. I don't think uploading GB or TB files online for scanning is an option to me. That will take a long time depends on the server network speed and my local network speed. (2) Privacy. I don't want to upload my files online. You can discuss that my files are not safe with offline scanner either or the online service will not share my files. But I still don't want to upload files for this purpose. Cheers.
    – sgon00
    Dec 23, 2021 at 4:08
  • @sgon00 sounds likey you want to perform a full manual system scan or at least a large subset. You did not include this info in your question.I also wrote that my answer is for scanning single files not a full system scan.
    – Robert
    Dec 23, 2021 at 9:09
  • Yeah, you wrote it. Sorry I missed the first sentence. I don't plan to perform full manual system scan. But a virtual scanner should have the ability to scan large files. Since Clamwin can not handle this properly that I mentioned in another thread. And web scanner is not an option either. I still don't know which tool I should use now. The most well-known free apps such as avast or avg can handle scanning task very well, but they turned off microsoft defender which is really bad.
    – sgon00
    Dec 23, 2021 at 9:55
  • @sgon00 Then I would recommend to check your favorite anti-virus vendor for their "removal tool". Most vendors provide a stand-alone (often portable) removal tool containing their engine and latest virus signatures for off-line scanning.
    – Robert
    Dec 23, 2021 at 11:46

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