18 Best Free On-Demand Virus Scanners

Start a virus scan quickly with a standalone tool

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 malware all the time like a traditional antivirus program.

So what good is one? 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 now hasn't caught it. Sometimes, a really nasty piece of malware will prevent your installed antivirus program from running properly, in which case one of these tools can come in handy.

Below is 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!

In many ways, online virus scanners are similar. If none of these tools work because your computer won't even load the operating system, consider a bootable antivirus tool.

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Malwarebytes scanning memory
What We Like
  • Catches all sorts of malware.

  • Easy to understand how to use.

  • Supports many languages.

  • Beginning a scan is easy through the context menu.

  • Premium features are free for a limited time.

What We Don't Like
  • Lots of features are missing in the free edition.

  • Asks often if you want to upgrade to the paid version.

Malwarebytes is one of the most popular free on-demand virus scanners. In our experience, it has found more malicious files than any other virus scanner we've used.

You can perform a threat scan to detect infections in locations malware normally hides, such as in the memory, registry, and file system. A custom scan can be launched as well, which scans any or all hard drives and folders with the option to include memory objects, startup items, the registry, archives, and rootkits.

Malwarebytes can also detect potentially unwanted programs (PUP) and modifications (PUM), start scans from the context menu in File Explorer, and exclude files/folders from scans.

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SUPERAntiSpyware Free Edition

Screenshot of SUPERAnySpyware Free Edition in Windows 7
SUPERAntiSpyware Free Edition. © Support.com
What We Like
  • Several scan types to choose from.

  • Many of the settings can be customized.

  • Includes other security tools.

What We Don't Like
  • Many features are reserved for the pro version.

  • Always shows a large ad.

SUPERAntiSpyware Free Edition 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 available like scanning just cookies and including/excluding particular folders from a scan. You can also use the free version to scan only the files running in memory, called a Critical Point Scan, which is useful if you think a piece of malware is currently running. This also gives you a quick view of potentially unwanted programs installed on your PC, and a dead-simple method to remove them.

There's a section of the program to show the applications that start up with Windows, as well as SUPERDelete, which lets you remove files that won't properly delete, and the ability to only scan files that were modified within a certain period of time.

Other useful tools and features are included as well, like a startup manager, ignoring large files, ignoring System Restore files, and scanning inside ZIP archives.

Something you might find annoying is that some of the options are only available in the Professional version, but it's not easily decipherable as to which features are or aren't. Clicking these areas will show an ad to download the full version.

Be sure to choose the red Download Free Edition button on the download page to avoid getting a trial copy of the professional version.

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Emsisoft Emergency Kit

Screenshot of Emsisoft Emergency Kit Scanner in Windows 10
What We Like
  • Extremely simple interface that's easy for anyone to use.

  • Doesn't need to be installed to the computer.

  • Provides advanced options if desired.

What We Don't Like
  • Large setup file might take a while to download.

  • Extracting the program files can be confusing for novice users.

  • Requires several hundred megabytes of storage space.

Emsisoft Emergency Kit scans for viruses, Trojans, spyware, rootkits, adware, PUPs, worms, etc., in a similar fashion as the programs in this list. You can exclude particular files and folders from a scan if you need to.

There aren't any ads, so you don't have to deal with a cluttered interface and it's easy to understand where you need to go to edit settings, access quarantined files, etc.

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Screenshot of the Stinger on-demand virus scanner
What We Like
  • Downloads quickly.

  • Runs from any location (it's portable).

  • The simple UI is easy to grasp.

  • Lets you pick specific scan targets.

What We Don't Like
  • Doesn't let you pause the virus scan.

  • Missing a built-in update option.

Stinger is a free, portable on-demand virus scanner from the same developers as the McAfee Antivirus software. Scan targets include running processes, boot sectors, registry keys, and rootkits.

You can create a custom scan to just search in particular directories and/or hard drives, or a complete scan that searches through everything. You can see the long list of threats it can find from the included Threat List.

Stinger can be set up to repair, report, rename, or remove malware. If you know the hash of files you don't want to be scanned, it lets you build a list of them so that the program skips over them.

The download size is around 20 MB and doesn't require installation, enabling Stinger to run from a flash drive or external hard drive.

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ClamWin Free Antivirus

ClamWin Free Antivirus
ClamWin Free Antivirus. © ClamWin Free Antivirus
What We Like
  • Can be installed or used as a portable program.

  • Includes unique features like email integration.

  • Supports scanning two types of targets.

  • Lots of advanced settings you can manipulate.

  • Scans can start automatically on a schedule.

What We Don't Like
  • Larger download than most on-demand virus scanners.

  • Installation is relatively slow due to definition updates.

  • No option to pause the scan.

  • Long time since last update.

ClamWin Free Antivirus is a free on-demand virus scanner that can be installed to Windows or launched from a removable USB drive.

It can scan just the system memory to find viruses that are currently running, or scan the entire file system (or specific files/folders) for malicious items.

Scheduled scans are supported as well as Window Shell integration, email alerts, file exclusions, and Microsoft Outlook email scanning.

The portable ClamWin Free Antivirus install is available through the ClamWin User Guides page.

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Dr.Web CureIt!

Dr.Web CureIt!
Dr.Web CureIt!. © Doctor Web
What We Like
  • It doesn't need to be installed.

  • Scans multiple threat types.

  • Lets you pause or stop a scan.

What We Don't Like
  • Comes in a large setup file.

  • Shows ads.

Dr.Web CureIt! is the exact same software as what's in the bootable Dr.Web LiveDisk program, but works within Windows instead of from a disc. It's a completely portable virus scanner, making it a great way to provide free on-demand virus scanning capabilities without having to install something.

You can scan boot sectors, the memory, the Windows folder, temporary files, system restore points, rootkits, or custom files and folders.

While Dr.Web CureIt! is portable, meaning you don't have to install anything to your computer, the download size is relatively large at over 200 MB.

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eScanAV Anti-Virus Toolkit (MWAV)

Screenshot of eScanAV Anti-Virus Toolkit in Windows 10
What We Like
  • Works from any portable location.

  • Includes several options for where to scan.

  • Supports different scan targets.

  • Can pause a scan.

  • Includes another useful security tool.

What We Don't Like
  • Larger download than most virus scanners.

  • Shows ads.

  • The scan results are hard to read.

eScanAV Anti-Virus Toolkit is a completely free portable virus scanner for Windows.

It checks for spyware, adware, keyloggers, and similar potentially malicious items running in the system memory. It can also scan an individual folder or whole disk drive. You have the option to just scan without repairing any files and to include scanning archive files.

Updates can be performed because the program installs itself to a temporary location while you use it. However, this is also a downfall because it means you have to run the setup file again if you wish to use the program in the future, given that all the files were unloaded to a seemingly undisclosed location on your computer.

Something else a bit bothersome about this program is that it displays an advertisement every time you close it.

The file is around 280 MB, so downloading MWAV may take some time.

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Microsoft Safety Scanner

Screenshot of Microsoft Safety Scanner

What We Like
  • Installation is unnecessary.

  • Uses a wizard to walk you through a scan.

  • Lack of advanced settings makes it really easy to use.

What We Don't Like
  • You have to re-download the program every so often.

  • Can't scan specific files only.

  • Doesn't provide an option to customize advanced settings.

  • Unable to pause scans.

Microsoft Safety Scanner is a free on-demand portable scanner from Microsoft that checks for and removes 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.

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.

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Norton Power Eraser

Screenshot of Norton Power Eraser

What We Like
  • Provides unique scanning features.

  • Simple interface that's easy to understand.

  • It's a portable application.

  • Has a small download size.

What We Don't Like
  • Pausing a scan is not supported.

  • There aren't many advanced settings that can be tweaked.

Norton Power Eraser is a portable on-demand free virus scanner that's just 10 MB in size.

The featured virus scanning function in this program is activated with the main button called Scan for Risks. This requires a reboot as it scans for rootkits. 

Choose Advanced Scans for other scanning methods. You can scan a file or folder with the 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 regular System Scan 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 the Multi-Boot Scan method to select the other OS that should be scanned.

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Sophos Virus Removal Tool

Screenshot of Sophos Virus Removal Tool in Windows 10
What We Like
  • It has a simple, easy-to-use interface.

  • Virus definitions are always up to date.

What We Don't Like
  • Your email address is required to get the download.

  • The program file is much bigger than other virus scanners.

  • It's always slow to start.

  • Lacks advanced options.

Sophos Virus Removal Tool is an on-demand free virus scanning tool for Windows that scans for viruses in the file system and memory.

Every time the program is started, it automatically begins an update to be sure its definitions are current, which is nice.

You won't find custom settings like file/folder exclusions, scheduled scanning, or context menu integration like similar products offer...there's not even a pause button. However, the scan is thorough and the program lets you remove any viruses it finds when it's finished.

It has to be installed to be used. It works with Windows XP and newer and is around 170 MB.

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Trend Micro HouseCall

Screenshot of Trend Micro HouseCall in Windows 10
What We Like
  • Provides multiple scan types.

  • It doesn't need to be installed.

  • You don't have to manually update the program.

  • Quick download.

What We Don't Like
  • Scans cannot be paused.

  • You can't pick what type of malware to scan for.

Trend Micro HouseCall is a portable, lightweight on-demand virus scanner for Windows. It finds and eliminates Trojans, viruses, worms, and spyware.

The program automatically updates when you open it so as to stay current with recent releases and definition updates.

You can run a quick scan, full scan, or custom scan to select specific folders and drives.

Trend Micro HouseCall is completely portable and just a few megabytes in size, making it ideal to place on a portable drive.

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Kaspersky Virus Removal Tool

Screenshot of Kaspersky Virus Removal Tool in Windows 10
What We Like
  • It's a portable virus scanner.

  • Lets you pick the scan target.

  • Provides multiple advanced settings.

  • Isn't hard to use.

What We Don't Like
  • Might take a while to download on a slow connection.

  • A scan cannot be paused, only stopped.

Kaspersky has a free on-demand virus scanner called Kaspersky Virus Removal Tool.

The program can scan system memory, hidden startup objects, boot sectors, archives, whole hard drives, and specific folders. There are also settings that let you scan certain file types only and skip files that are taking too long to scan.

Kaspersky Virus Removal Tool is over 150 MB and can be used as a portable antivirus program that doesn't require installation.

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Norman Malware Cleaner

Norman Malware Cleaner
Norman Malware Cleaner. © Norman Shark AS
What We Like
  • Lets you customize advanced settings.

  • Includes unique features.

  • Runs as a portable program.

What We Don't Like
  • Takes a while to download.

Norman Malware Cleaner is an on-demand virus scanner for Windows that's portable and free to use.

It scans inside archives, searches for fake antivirus software, identifies rootkits, and detects malicious items running in system memory. There's also a Forensics section to scan running files to find anything that looks suspicious and could possibly be malicious.

Options are available to exclude files and folders from a scan and to delete or restore quarantined items that it has found.

The download size is around 300 MB. It's so large because the program isn't installed to your computer but instead ran as a portable app.

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Comodo Cleaning Essentials

Screenshot of Comodo Cleaning Essentials in Windows 8
Comodo Cleaning Essentials.
What We Like
  • Includes lots of unique, useful tools and options.

  • You can choose the types of threats to check for.

  • No installation necessary.

  • Advanced options let you customize specific parts of the scan.

  • Scans can be paused.

What We Don't Like
  • Requires a restart after some scans, even if threats were not detected.

Comodo Cleaning Essentials is a portable virus and rootkit scanner. You can run a smart scan to scan critical areas of the computer or do a full or custom scan.

If you choose a custom scan, you can scan in the memory, critical areas and boot sector, hidden registry objects and services, and/or hidden files and folders.

You can even choose to disable the virus scan so you can check for malicious items in the memory only, for example, instead of searching through the whole computer.

Advanced settings are available such as scanning in archives, excluding large files from a scan, scanning for suspicious MBR modifications, and enabling the creation of restore points before running a scan.

Comodo Cleaning Essentials also includes Autorun Analyzer, which is used for viewing all the programs, drivers, scheduled tasks, and other things that launch when Windows starts. Also available is KillSwitch, which lets you shut down running programs, processes, and network connections.

If you can't get into Windows to start a scan, try Comodo Rescue Disk.

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Panda Cloud Cleaner

Screenshot of Panda Cloud Cleaner in Windows 10
What We Like
  • Includes helpful features not found in other scanners.

  • Simple interface that isn't confusing to use.

  • Installs quickly.

What We Don't Like
  • Missing the option to pause a scan.

  • Shows ads.

The developers of Panda Dome also have an on-demand tool for Windows that can scan for viruses, called Panda Cloud Cleaner.

It scans the registry, system memory, and other common locations where malware could be hiding. You can also scan individual files and folders, shut down all running processes, unlock files, and submit suspicious files to Panda for analysis.

The download is relatively small but you do have to install it.

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Zillya! Scanner

Zillya! Scanner
© Zillya!
What We Like
  • It's a portable scanner.

  • Run a scan against specific kinds of files.

  • Multiple scan types.

  • Has a bare interface that's void of anything confusing.

  • Pausing is supported.

What We Don't Like
  • Might take long to download on a slow connection.

  • Doesn't provide advanced scan settings like some programs.

Zillya! Scanner is a free on-demand portable virus scanner for Windows from the same developers as Zillya! Antivirus.

You can run a quick scan to find viruses in sensitive folders, a full scan to scan every area of a drive, or a custom scan to choose particular folders, files, and drives to scan.

When running a custom scan, you have the option to just check potentially dangerous file types only so that it doesn't have to scan every single file.

The download requires 190 MB of disk space.

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F-Secure Online Scanner

F-Secure Online Scanner
What We Like
  • One of the easier-to-use virus scanners.

  • Viruses are deleted automatically.

  • Checks multiple locations for viruses.

  • Installing is unnecessary.

  • Small download size.

What We Don't Like
  • There aren't any advanced settings that can be customized.

  • You can't review the threats before they're deleted.

  • Doesn't let you pick which folders to scan.

  • Pausing is not supported.

F-Secure Online Scanner is another free on-demand portable virus scanner. This program doesn't scan every location on a PC, but instead looks through folders where viruses are normally found.

There are absolutely zero custom settings in F-Secure Online Scanner. If it finds a virus, it's removed without question and doesn't prompt you to decide to keep it.

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VIPRE Rescue

Screenshot of VIPRE Rescue
VIPRE Rescue. © ThreatTrack Security, Inc.
What We Like
  • Deletes viruses automatically.

  • It's easy to understand how to use.

  • The program runs from anywhere (it's portable).

What We Don't Like
  • Requires lots of disk space.

  • Doesn't provide a graphical user interface.

  • Won't ask which threats to remove.

  • Unable to customize the scan.

VIPRE Rescue is a portable, on-demand free virus scanner. It doesn't have a user interface but, instead, runs through Command Prompt.

After downloading it (which is over 400 MB), the installer will ask you to extract the files to a folder. The default folder is C:\VIPRERESCUE\ but you can change it to whatever you want.

It will run the program automatically after the extraction, but if not, open the extracted files and run VipreRescueScanner.exe. A scan will immediately start and will automatically remove any viruses it finds.

We recommend only using this program if every other scanner in this list fails to install due to a virus infection. There aren't advanced options and it's too easy to accidentally stop the scan by exiting Command Prompt.

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