An on-demand virus scanner is an antivirus program that you run only when you want to run it – it doesn’t protect you from viruses and other malwareÂ all the timeÂ like those that I’ve written about in myÂ Best Free Antivirus ProgramsÂ list.
So what good is an on-demand virus scanner? These types of antimalware tools are great when you think you might have some kind of virus or other malware but the antivirus program you’re using then, hasn’t caught it. Sometimes a really nasty piece of malware will prevent your installed antivirus program from running properly, in which case an on-demand virus scanner can come in handy.
Here’s a complete list of the very best free on-demand virus scanners available. Many of these programs even come in a portable version, meaning no installation required!
Malwarebytes Anti-Malware is one of the most popular free on-demand virus scanners. In my experience, it has found more malicious files than any other virus scanner I’ve used.
You can perform a quick scan, which detects infections in sensitive locations only like theÂ WindowsÂ folder, or aÂ full scan, which scans every single directory on your computer.
You can ignore files and folders to preventÂ Malwareybytes Anti-Malware from including them in a scan, enable archive scanning, and optionally scan memory objects, startup items, and registry entries.
Malwareybytes Anti-Malware also supports starting scans from the context menu in Windows Explorer.
SUPERAntiSpyware Free EditionÂ is a free on-demand virus scanner that detects spyware in the registry and file system as well as those running in memory.
Some advanced settings are availableÂ like scanning just cookies and including/excluding particular folders from a scan.
Something I find very annoying withÂ SUPERAntiSpyware Free Edition is that some of the options are only available in theÂ ProfessionalÂ version, but it’s not easily decipherable as to which features are or aren’t. Clicking these areasÂ willÂ show an ad to download the full version, which can get annoying.
Note:Â Be sure to choose theÂ Download Free Version Home UsersÂ button on the download page to get the free edition ofÂ SUPERAntiSpyware.
Emsisoft Emergency Kit provides on-demand virus scanning via 4 built-in tools that run from a singleÂ program suite that can be launched and even updated from a portable location.
Emergency Kit ScannerÂ is one of the included tools that scans for viruses, Trojans, spyware, adware, worms, etc., in aÂ similar fashion as theÂ programs in this list.Â This should be your first option when using Emsisoft Emergency Kit.
TheÂ Commandline ScannerÂ is just like the previous scanner but doesn’t use a graphical interface. Instead, it runs entirely from a command line interface and should be usedÂ mainly for advanced users.
Next is a tool calledÂ HiJackFree, which is a very comprehensive tool that can shut down running processes, ports, services, and programs that automatically start when you sign on to Windows. This is used if you’re monitoring a malicious program and need to terminate it from accessing the Internet. It clearly shows processes that have been signed as secure and lets you easily filter the results to find ones that could be infectious and unwanted. Then you can either shutdown the process or completely remove the malicious file.
The final tool, to be used with great caution, isÂ BlitzBlank. This program schedules registry entries and drivers to be removed when the computer reboots, which is perfect if the malware is preventing itself from being shutdown under normal conditions. This tool is very powerful, so it can be destructive if used inappropriately.
Stinger is a portable and free on-demand virus scanner from the same developers as the McAfee Antivirus software.
You can create a custom scan with Stinger to just search in particular directories, or a complete scan that searches all folders, running processes, boot sectors, andÂ registry keys for rootkits and a whole list of other specific threats.
The download size is just over 10 MB and doesn’t require installation, enabling Stinger to be ran from a portable device.
Note:Â To download Stinger, move to the very bottom of the download page and click theÂ Download NowÂ link.
ClamWin Free Antivirus is a free on-demand virus scanner that can be installed to Windows or launchedÂ from a removable USB drive.
ClamWin Free Antivirus can scan just the system memory to find viruses that are currently running, or scan the entire file system for malicious items. You can choose to scan a whole drive for viruses or just a particular file or folder.
Scheduled scans are supported in ClamWin Free Antivirus, as well as Window Shell integration, email alerts, file exclusions, and Microsoft Outlook email scanning.
Note:Â The portableÂ ClamWin Free AntivirusÂ install is available from theClamWin User GuidesÂ page, and not the link below.
6.Â Dr.Web CureIt!
Dr.Web CureIt! is a portable application for Windows that provides free on-demand virus scanning capabilities.
You can scan boot sectors, the memory, the Windows folder, temporary files, system restore points, rootkits, or custom files and folders.
Dr.Web CureIt! isÂ portable, so you don’t install anything to your computer. However, the download sizeÂ is rather largeÂ at almost 140 MB.
Note:Â On the download page, you must first accept the license agreement to get the Dr.Web CureIt! program.
EMCO Malware Destroyer is a free program for Windows that provides quick and on-demand virus scanning.
The following threats are scanned for with EMCO Malware Destroyer: Adware, viruses, Trojans, worms, dialers, spyware, and suspicious programs.
Thousands of virus signaturesÂ are scanned against the PC in question, and they’re always being updated. This meansÂ EMCO Malware Destroyer is a good choice against both new and old threats.
While testing the program, a full system scan took less than 30 seconds to complete,Â making it one of the fastest on-demand virus scanners from this list.
eScanAV Anti-Virus Toolkit is a completely portable free on-demand virus scanner for Windows.
It checks for spyware, adware, keyloggers, and similar potentially malicious items running in the system memory. eScanAV Anti-Virus Toolkit can also scan an individual folder or whole disk drive.
You have the option to just scan without repairing any files, as well as the option toÂ include scanning archive files.
Updates can be performed because eScanAV Anti-Virus installs itself to a temporary location while you use the program.
You can also use eScanAV Anti-Virus Toolkit to view and terminate connections to the Internet, which is useful if you suspect a malicious program is accessing the Internet.
Something a bit bothersome about this program is that it displays an advertisement every time you close it.
Microsoft Safety Scanner is a free on-demand portable scanner from Microsoft that checks for and removesÂ spyware and similar malicious files.
You can run a quick scan to check only critical areas where viruses may be resting, a full scan to check every file and folder on your PC, or a custom scan to couple a quick scan with a scan of any other folder of your choosing.
The installer file for Microsoft Safety Scanner is about 100 MB and runs as a portable application.
Note:Â After 10 days, you’re required to download the setup file again if you wish to make another scan. This is to ensure you have the latest definitions to fight malware.
10.Â Norton Power Eraser
Norton Power Eraser is a portableÂ on-demand free virus scanner that’s just under 3 MB in size.
The featuredÂ virus scanning function in Norton Power Eraser is activated with the main button calledÂ Scan for RisksÂ on the first window of the program. This requires a reboot as it scans for rootkits.
ChooseÂ Advanced OptionsÂ for otherÂ scanning methods.Â You can scan a file or folder with theÂ Reputation Scan, which performs a cloud lookup on the data. This requires an active Internet connection, so Norton Power Eraser can upload the necessary information to the Internet.
Another method is the regularÂ System ScanÂ option, which scans the current Windows operating system for viruses. The third and final option is similar to the second and is only effective if you’re running more than one Windows operating system. If that’s the case, you can use theÂ Multi-Boot ScanÂ method to select the other OS that should be scanned.