How To Identify and Remove the MSASCuiL.exe Virus

What is the MSASCuiL.exe executable, and what tips can help you delete and prevent infections from taking over your computer?
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The MSASCuiL.exe process is, at its simplest, a way to show the icon for Windows Security in the taskbar. The name stands for Microsoft Antivirus Security Center User Interface Logo. The .exe file itself is not a virus but has the potential to be spoofed.

Spoofing valid executables and Windows processes is a popular way of installing malware. There’s a chance that the file, looking like something reputable, will get through a firewall or blacklist antivirus software’s defenses. It’s for these reasons that you may end up with a virus that looks like a valid part of your Microsoft Windows operating system.

Luckily, malware that spoofs valid processes is fairly easy to remove with a good antivirus program or PC cleaner. You should be able to restore your machine to the way it worked before the virus. The method for removal is quick and only requires a few steps.

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In this article
Is MSASCuiL.exe a virus?
How to know if you have the MSASCuiL.exe virus
How to remove the MSASCuiL.exe virus
How to avoid malware
MSASCuiL.exe FAQ
Bottom line

Is MSASCuiL.exe a virus?

No, the true form of the MSASCuiL.exe startup file is not a virus. Ironically enough, the executable is part of Microsoft’s proprietary antivirus program, Windows Defender, that's meant to protect your computer from viruses. The main function of this particular executable in the software design is to show the Windows Security icon in your taskbar. It looks similar to the executable file MSASCui.exe, which is the actual file name for the Windows Defender program.

It’s very important you do not delete or disable either of these executables without the assistance of a reputable antivirus.

People who write the code for Trojan horses and other types of viruses will often give their malware similar names to valid systems, processes, and executables in an attempt to thwart subpar antivirus programs. The malware can even, on occasion, get past reputable antivirus software because of the similarities. Luckily, antivirus programs are still able to recognize the virus.

How to know if you have the MSASCuiL.exe virus

If you notice a significant slowdown in your computer’s functionality or unusual behavior, you may have the virus. Unusual behavior may look like significant CPU usage when you open the Task Manager or system settings you don’t remember changing. There may even be odd pop-ups on your screen or a change to your web settings. In any of these cases, it’s best to check for a virus.

To begin to check for the virus form of MSASCuiL.exe, you can look at what folder it lives in. The legitimate executable's file location is C:\ProgramFiles\WindowsDefender and it has a small file size.

If you find MSASCuiL.exe in another folder or the file size is above 640KB, it’s likely to be a virus. The average size of the legitimate executable is between 470KBs and 640KBs; anything in this range is normal.

If anything looks suspicious, it’s best to run a scan through your antivirus software. It’s worth noting again that you should not attempt to remove this on your own as you may remove a legitimate executable that could render your operating system useless.

How to remove the MSASCuiL.exe virus

Run an antivirus

Start by running a full scan on your computer using your antivirus software. If your scan is set to automatically quarantine and delete malicious programs and files, you can check in what’s been done to see if MSASCuiL.exe was part of the clean-up.

If you don’t have antivirus software, or you want something other than Windows Security, consider one of these programs that performed exceptionally well during testing:

  • McAfee: If you're worried your family computer is infected with the MSASCuiL.exe virus, look to McAfee to get rid of it. For future protection, McAfee offers parental controls to help you keep your kids from visiting potentially malicious websites. We also love that McAfee earned perfect protection scores in the latest third-party tests.

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  • AVG: Another antivirus with perfect protection scores in the latest tests, AVG goes the extra mile with tools like a phishing site blocker, ad- and tracker-blocking, and even a Wi-Fi network scanner to make sure you don't accidentally join a spoofed network. We also love that AVG comes as a free version so you can give it a try, no credit card required.

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  • Norton: An oldie but a goodie, Norton also earned perfect protection scores. We're not surprised, since this cybersecurity giant offers plenty of features like a phishing site blocker, firewall (for Windows), an intrusion protection system, and proactive exploit protection. This means your devices are protected from even the nastiest malware — whether it was invented a decade ago or yesterday.

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Norton lets you pair its powerful antivirus software with LifeLock, one of the best-known identity protection services around. This double layer of protection keeps your data, devices, and personal identity safe from hackers and thieves.

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Remove the MSASCuiL.exe virus and infected files

If your antivirus scan is set to manual, you can look at the files identified and then opt to have them cleaned and quarantined. You should have your antivirus software clean and remove all infected files it finds on your computer.

It’s worth noting that a reputable MSASCuiL.exe executable will not show up in your virus scan results. The reputable version is signed by Microsoft and recognized as a good system file by your security software.

Word of warning: There’s a lot of misinformation on the internet about how to uninstall this file from the source. Again, please do not attempt to remove it without an antivirus or cleaning tool. You may end up removing a legitimate process and permanently damaging your computer.

Restart your device and scan again

The best way to know if all instances of the virus are removed is to restart your computer and perform another scan. Scanning again allows you to make sure no pieces of the virus were able to escape the first scan and clean, and also makes sure all processes are running correctly.

If you do not see any malicious files in your second scan, you’ve removed the virus.

How to avoid malware

The internet is an amazing tool that’s also a hotbed of nefarious activity. While it’s not completely possible to avoid all malicious intent all the time forever, it is possible to reduce your chances of contracting malware. Use some tips below to stay safe online.

Use antivirus software

You wouldn’t get in a car without buckling your seatbelt. Connecting to the internet with antivirus software is like having a seatbelt on as you speed around the information superhighway. Knowing how your antivirus software protects your devices from malicious files like spyware, adware, and even ransomware can also help you understand what to avoid.

Be careful of suspicious links or attachments

Phishing emails can look quite funny with misspelled words or odd proportions, especially if cybercriminals are trying to spoof a recognizable source like your bank. But more often now, phishing emails can look pretty credible. Remember not to click links or open attachments unless you’re 100% sure they’re safe.

Create complex passwords

A password can be the difference between becoming a victim and protecting your data. Strong passwords create a good line of defense in keeping sensitive information private. Create something unique and difficult to guess.

Ignore unknown messages

Social media is rife with spammers and phishers looking to find a way into your computer or to harvest your data. If you receive a message from someone outside of your circle of contacts, it’s best to ignore it. If you think you may know them, check out their profile to see if it looks like a real person.

Be suspicious of duplicate accounts

If you receive a friend request on social media from someone you already know, it’s likely a hacker has duplicated their account in an attempt to gain access to their friends. If someone you are already friends with sends you another friend request from a duplicate account, be suspicious. Usually, these fake accounts use the same profile picture as the person they’re spoofing.

Once you engage, they send you a link that’s likely a phishing scam. You can check by going to your friends/followers list and seeing if the original person is still there. If they are, it’s likely this is a scammer.

Download files and media from reputable sources

So maybe we don’t live in the generation of Napster anymore, but that doesn’t mean there aren’t plenty of places to illegally download content. Make sure you trust the source you’re downloading from when putting new files on your device.

Disclaimer: We do not condone pirated software or media, but we know people will still try to download these items. Purchasing and downloading content from its original source is one of the only ways to know the files aren’t corrupted or containing malware.

Use a VPN

A virtual private network (VPN) is good for more than just watching Netflix content from other regions. It encrypts your data and protects your IP address from digital Peeping Toms. This can help keep you safe while using public WiFi where someone may attempt to access your computer and deposit malware like MSASCuiL.exe wirelessly.

Keep your software patches updated

Outdated software is a great way to leave your computer open to viruses. Software developers release regular patches as a way to fix security holes. The internet is a constantly evolving environment that requires constantly evolving security measures. Software updates may be annoying, but they’re a great line of defense against the latest infections.

MSASCuiL.exe FAQ


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What is MSASCuiL.exe?

It’s a legitimate executable that allows the icon for Windows Security to show up in your taskbar. It’s found in the Program Files folder and has minimal CPU usage as well as a smaller file size. If any of these are off, like a different folder, high CPU usage, or a larger file size, it’s likely a version of a virus meant to look like MSASCuiL.exe


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How is the MSASCuiL.exe virus spread?

MSASCuiL.exe is spread through malicious email attachments, infected online advertisements, social engineering attacks, and unpatched software. You can pick this virus up by clicking on infected links or attachments as well as having out-of-date security software.


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How do I know if my computer has the MSASCuiL.exe virus?

Your computer may be slower, CPU usage could be increased, or settings or preferences could be changed without your knowledge. You can search your folders for the MSASCuiL.exe command and see if it’s located only in C:\ ProgramFiles\ WindowsDefender on your hard drive. If located anywhere else, it’s likely a virus.

Bottom line

While MSASCuiL.exe is a legitimate Windows executable, there is malware out there designed to look similar. This malware can slow down your computer, steal your passwords, compromise your financial security, and add you to a nefarious botnet army meant to launch DDoS attacks. (This sounds dramatic, but it’s true!)

Using reputable antivirus software can help protect your computer from becoming infected with malware like MSASCuiL.exe and other malicious software. It can also help you remove viruses if they do find their way onto your machines. In fact, using an antivirus or cleaning tool is the only recommended way of removing malware files that spoof legitimate processes like MSASCuiL.exe. This can help to make sure you don’t delete essential parts of your operating system.

By following the tips above and staying diligent about your online interactions, you can reduce your chances of contracting viruses and other malicious software. Enjoying the internet is something we should all be able to do without the fear of getting hacked.

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Author Details
Mary is a seasoned cybersecurity writer with over seven years of experience. With a B.S. in Liberal Arts from Clarion University and an M.F.A. in Creative Writing from Point Park University, she educates audiences on scams, antivirus software, and more. Her passion lies in educating audiences on helpful ways to protect their data.