Best Free "Second Opinion" Malware Scanner





Almost everyone who cares about security runs some kind of basic antivirus protection. Traditional antivirus protection works great for most users but no software is perfect. We live in a world full of security holes and bugs where patches and updates try to come to the rescue at the end of the day.

While capabilities of antiviruses have evolved over time adding layers of protection, so has malware themselves being able to compromise any system they get their hands on. As the contest and quarrel of the "Best antivirus software" goes on and on, the intelligent few accept that nothing is perfect and use a secondary opinion scanner to confirm their systems are actually safe. Also the unlucky few who were infected finally turn their heads to these on-demand scanners to remove persistent malware. 

Second opinion scanners are neither meant to replace traditional antivirus suites nor to be used in real-time on your system. They are only meant to be run either to ensure your system is free of malware, or to remove malware from a heavily infected system or even to remove potentially unwanted programs and annoying adware that an antivirus mostly misses. Ideally they are required to be run only once a month or on-demand and are your second line of defense against these bad guys!


Feature Pre-requisites

Here are some of the features that I'm looking forward to when choosing a secondary opinon/on-demand scanner. Real-time protection is not included here and not necessary as we're looking for on-demand scanners only. 

  • Scan for Active rootkits - Type of malware that manipulates the system in a way that causes it not to show specific information/files anymore;
  • Scan for Active malware in memory - scans all currently loaded programs and their components;
  • Scan for Malware traces - manipulated registry settings or non executable malware data or configuration files that are indicative of an infection;
  • Scan for PUPs, PUMs - programs that are not dangerous by definition but are usually unwanted by most users as they display ads or manipulate browsers;
  • Scan inside compressed archives - malware might hide here, but to scan them takes a longer time;
  • Scan in email data files (optional) - external e-Mail clients, scanning of such files takes time;
  • Scan in NTFS alternate data streams - hidden layers in regular files that may be used to hide malicious code;
  • Scan based on File extension filter - scan only specific file types;
  • Use direct disk access for scan (optional) - more effective but slower alternate method of reading files from HDD for scanning. Only for finding rootkits. It is great but not for entire HDD;
  • File reputation - Upload and scan unknown or suspicious objects by comparing with community reviews or cloud engines;
  • Multiple scan options - Ideally have Quick scan, Full scan and Custom scan option;
  • Cloud features - storing malware definitions on the cloud and not taking up HDD space;
  • Multiple scan engines - for better detection rates and reduce outbreak exposure times but prone to false positives;
  • Quarantine ability - safe place for detected objects where they can't do any harm and ability to delete objects permanently from here;
  • Logs & Reports - provide extensive component and action reports with export features and detailed view.


Rated Products

Emsisoft Emergency Kit  

Portable anti-malware with best-in-class malware signatures

Our Rating: 
License: Free
Pleasing GUI, portable installer, easy to use, fast scan speeds, uses Bitdefender database, good at detecting old malware and malicious registry keys, effective against PUP's and adware, able to implement direct disk access and scan in NTFS alternate data streams.
Huge download size, large updates, no proper cloud implementation, poor against new and fileless malware, occasional pop-up ads.
Read full review...

Zemana AntiMalware  

Cloud based anti-malware powered by multiple engines

Our Rating: 
License: Free (Limited features)
Small download size, high PUP/adware detection, strongest against fileless malware and active malware processes, cloud based, drag n drop scan support, good signatures, doesn't require updates, portable version available.
Slow scans, not good against zero-day malware, Zemana v2 better than v3, prone to false positives, requires 2 separate scans for best protection.
Read full review...


Best malware scanner in the category but no free removal capability

Our Rating: 
License: Commercial (Trial/Demo available)
Fully portable, cloud based, powerful scanner, no signature update required, 4 popular scan engines with VT integration, early score warning to combat zero-day malware, fast scan speed, direct disk access mode, best against old & new malware and PUP's, scheduled scans.
Free scans but no free removal, performs poorly against fileless malware.
Read full review...

Norton Power Eraser  

Aggressive scanner with file reputation technology to beat malware

Our Rating: 
License: Free
Very fast scanning speed, doesn't require signature, fully portable, multi-boot scan, Norton's file reputation to detect malware/PUP's, strong at detecting malicious registry keys, auto restore point creation, cloud lookup, option to undo previous fixes.
Aggressive scans hence prone to false positives, no progress bar for scan status, poor log reports, requires multiple scan types, mostly reputation based scans.
Read full review...

Malwarebytes Anti-malware  

Best crime fighter against PUP's/adware

Our Rating: 
License: Free (Limited features)
Best PUP & PUM detection, very fast scan speeds, self protection modules, performs well against new ransomware and malicious registry keys, has very good heuristics, brilliant exclusion settings, identified thread logs during scan, signature-less anomaly detection for increased protection.
No portable version, turns premium trial on by default and produces nag screen if turned off, poor against regular malware and zero-day threats, no cloud engines, needs to download signatures, auto startup on boot by default.
Read full review...


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Your rating: None
Average: 4.2 (25 votes)


Oops, sorry MC. Thought I was posting to the specific review. I'm referring to the Zemana Anti malware

Zemana has a portable version for v2.74 and an installer version for v3.0. I have reviewed v2.74 in this article because it's better than v3.0 which removed some cool features of v2.74, and their creator has left the company, I believe. 

Zemana like other Second opinion scanners here doesn't have real-time protection, which is why it's listed as trial version in download page with an option to upgrade. However scanning and removal of malware is totally free. 


Thanks for the explanation George.J. MC - Site Manager.

As far as I can make out this is the freeware link and I've also changed this in the product details. MC - Site Manager
"The free version of Zemana AntiMalware isn't exactly packed with features, but the upside is that new users should have no problems figuring out how everything works. A scan can be launched in just a few seconds, and it will be over almost as quickly. No scanning options need to be configured, as one click is all it takes."

I may be missing something, but after going to multiple websites ,including the link in your article,I cannot find a free version of this app. Only a 30 day trial version appears to be available. I did find the portable version but that too is a 30 day trial.

Which 'app' are you referring to? MC - Site Manager.

You constantly show these programs, but it is nearly impossible to find the link and this particular "freeware" has no link at all.

All the program download links are visible and working for me, what exactly are you referring to? MC - Site Manager.

You need to click on the name of the Software (eg. Zemana Antimalware) to view the download link or in the "Full review" section. 


Excellent review but you say to use weekly and to use only on demand -- what about a free REAL-TIME PROTECTION as opposed to just scanning on demand, IF the user remembers to do the scanning?

Please read the article text. "Second opinion scanners are neither meant to replace traditional antivirus suites nor to be used in real-time on your system". Real-time protection software is reviewed here. MC - Site Manager.