Free On-Demand Scanners Compared

I'm on record as not being in favour of obsessive running of on-demand scans (for a 2nd opinion to your AV) when one's system is running well. In my experience most of what they find are false positive (FP) detections. (Of course, if your system is acting up, all bets are off). And I am aware of no independent tests that compare the efficacy of these free scanners at removing malware.

Nonetheless, I think everyone should have at least one or two good backup scanners installed for that proverbial "rainy day". There are several good online backup AV scanners available, but they won't help you if malware messes with your internet connection, and I won't discuss them here. (The online AVs do take a lot more time to scan your system).

In this post I will review the various scanners I am familiar with, and use. As always, I will not focus on efficacy of detection of malware (I'm not qualified) but rather on ease of use, and potential advantages/disadvantages. All scanners reviewed are the freeware versions, using default settings. AFAIK, all scanners are supported by Win XP and newer OSs. In every case I used only the quickest scan available, and configured the scanners to report detections only (Not remove, repair, delete, or quarantine detections). Programs are reviewed in no particular order.

Testbed: Windows 7 (64 bit) Home Premium, Dell XPS 8300, fast cable connection.

1) Emsisoft Anti-Malware Free 8.0.0.10
Download: http://www.emsisoft.com/en/software/antimalware/download/
Support Forum: http://support.emsisoft.com/forum/52-emsisoft-anti-malware/
- Formerly known as a-squared. Despite its name ("anti-malware") it does incorporate 2 scan engines: an anti-malware developed by Emsisoft, and an AV engine from Bitdefender, which rates highly as an AV. It includes removal capability.
- Historically, EAM used to have a fair number of false positives, particularly when it used the Ikarus AV engine. It has been a few years since I detected any FPs with this scanner. I attribute this to EAM switching from Ikarus to Bitdefender.
- Manual updates from within the program are required. When done weekly, they take only a minute or so. New versions or builds are included in these updates.
- Can be integrated into Explorer, to allow scanning of individual files (via a right-click) from the context menu.
- No splash screens, nags to upgrade, ads or bundled software included.
- Stores logs of all scans automatically.
- Quick Scan time: about 20 sec.
Suggested usage: Only when you have problems with your system.

2) HitmanPro 3.7.6
Download: http://www.surfright.nl/en/hitmanpro/
Support Forum: None
- A "cloud" AV, it requires no updating of its signature files. It will update the program automatically, when the program is opened, to the latest version/build. It will not conflict  with your resident "real-time" AV.
- Extremely simple, no configuration required.
- Uses 4 engines (G Data, Bitdefender, Ikarus, Emsisoft) that scan only selected critical  areas of your system for viruses and malware.
- As a cloud AV, if malware kills your internet connection, you are out of luck.
- Very few false positives, if any, in my experience.
- No removal capability in this free version.
-  Integrated into Explorer, to allow scanning of individual files.
- No splash screens, ads, nags, or bundled add-ons.
- Stores logs of scans only if manually selected.
- Quick Scan time: about one minute.
Suggested usage: Safe for daily usage, as the free version will not remove/quarantine false positives. Its use of 4 reputable AV engines is a positive.

3) Malwarebytes Anti-Malware (MBAM) 1.75x
Download: http://www.malwarebytes.org/
Support Forum: http://forums.malwarebytes.org/index.php?s=1a437a3a7078e7889c5b7de95f1f0740&showforum=41
- Possibly the best anti-malware scanner, which both detects and removes malware. Commonly recommended by malware-removal experts when your system has gone south.
- Highly configurable.
- Integrated into Explorer, to allow scanning of individual files.
- Very few false positives, which are rapidly corrected (usually within hours) with new signature updates.
- No splash screens, ads, nags, or bundled add-ons.
- Stores logs of all scans automatically.
-  Quick  Scan time: about 3 minutes.
Suggested usage: Only when you have problems with your system.

4) MS Malicious Software Removal Tool (MSRT)
- A new version is released every month, on "Patch Tuesday" (the 2nd Tuesday every month). It scans and deletes prevalent malicious software.
- Download: http://www.microsoft.com/en-us/download/malicious-software-removal-tool-details.aspx
- Not configurable
- I am unaware of any reports of false positive detections with this tool.
- No splash screens, ads, nags, or bundled add-ons.
- Displays a log of the most recent scan only.
- Quick Scan time: less than one minute. (Full scan can take hours).
Suggested usage: Safe to run whenever. I generally run a quick scan only monthly on release.

5) SUPERAntiSpyware Free Edition v5.6x
Download: http://www.superantispyware.com/
Support Forum: http://forums.superantispyware.com/
- Claims to detect and remove all sorts of malware. In practice, I find SAS useful at detecting tracking cookies that other scanners do not.
- The installer comes bundled with Google Chrome browser pre-checked by default. Be sure to uncheck this if you don't want it.
- A bit more nags and ads than the others.
- Integrated into Explorer, to allow scanning of individual files.
- Comes with a nice repair toolkit, which I have yet had to use.
- Requires manual signature and program updates. Usually quick, if performed regularly.
- Although not noted for frequent false positives, a recent fiasco crippled several legitimate programs. SAS was not quick to correct this problem.
- Scan time: about 30 sec. (Using the "Critical Point Scan". A "Quick Scan" takes about 2 minutes).
Suggested usage: Only when you have problems with your system. Probably not the best scanner to run first.

6) ClamWin Free AV 0.97.8
Download: http://www.clamwin.com/content/view/18/46/
Support Forum: http://forums.clamwin.com/
- This free AV scanner runs only on-demand, providing no real-time protection.
- No add-ons or bundled software.
- Can be configured to "Report only", "Remove", or "Quarantine" anything detected.
- It offers only one scanner, that is not "Quick". It took 86 minutes to scan.
- It detected a lot of False Positives, including several WinPatrol installers (wpsetup.exe)
- Suggested usage: Not recommended, due to long scan times and false positives.

7) McAfee Stinger
Download: http://www.mcafee.com/ca/downloads/free-tools/stinger.aspx
Support forum: https://community.mcafee.com/community/home/other_mcafee_consumer_products
- Stinger is a free utility that both detects and can remove specific viruses, trojans and variants (currently over 6200 in its list.)
- No add-ons or bundled software.
- Having used it sporadically for years, I cannot recall any false positive detections.
- Quick scan time: about one minute.
- Can be configured to "Report", "Remove", or "Repair" detections. As with all my scanners, I use "Report" only.
- Frequent updates required, that have to be done manually.
- Suggested usage: Only when you have problems with your system.
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Notes:

- Scan times on my system are reported for comparative purposes only. Your actual times will vary according to the hardware, operating system and internet connection you use. However, I am impressed with how most of these scanners have decreased their scan times over the years. But to be honest, when your system has malware, I don't think scan times should be major consideration when choosing a scanner.

- None of these on-demand scanners should impact system/browser performance or resources. None should conflict with your installed AV or Security suite, but be aware that some security products are very "territorial" and will flag these (and other) on-demand scanners as incompatible. I can confirm only that all these scanners co-exist nicely with my avast! Free and MSE AVs.