Ads by System: what it is and how to remove it

Developed by MC Software Inc, System-Checker is a deceptive application that is not recommended using. However, be aware that neither the program itself nor the service it offers, which is to allow users to monitor various system-related information, including CPU, memory, and system load, are harmful.

Facts checked October 7, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.

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Ads by System: uninstall from windows 1
Ads by System as our 2021 report showed it.

Ads by System: summary

Detection namesNo Microsoft detection name is known
DistributionNot recorded in the old report
DamageNot recorded in the old report
NameAds by System
TypeAd-supported program
SymptomsAn unknown program in Installed apps
Removal

Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged.

Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free.
Show 4 more facts
EvidenceOne write-up by a security site; details still limited
ProgramAds by System
First seen26 April 2021
Facts checked7 October 2026

Is Ads by System dangerous?

From our report of Apr 2021 · not reviewed since

What is System-Checker?

Developed by MC Software Inc, System-Checker is a deceptive application that is not recommended using.

However, be aware that neither the program itself nor the service it offers, which is to allow users to monitor various system-related information, including CPU, memory, and system load, are harmful. However, System-Checker is sponsored by third parties and may also try to promote third-parties by delivering sponsored content while you are browsing.

Computer's security experts have already labeled it as an adware and a potentially unwanted program (PUP), whereas developers of reputable anti-malwares have inserted PUP.System-Checker and adware.System-Checker to the virus databases. The majority of activities that System-Checker virus is set to implement to marketing purposes are initiated behind user's back.

For example, it may continuously connect to the Internet in order to download updates (or maybe other third-party apps), step-by-step affect your computer's security system in order to increase vulnerabilities or may run various processes (e.g. two System-Checker.exe in Task Manager) in order to burden the system and slow it down.

Even more, it may hijack each of your web browser (Google Chrome, Mozilla Firefox, Internet Explorer, Safari), modify settings and install cookies on each of them. Consequently, it may continuously track you and accumulate non-personal data about your browsing habits. However, there is one prominent sign indicating that this adware hides in your computer.

Once installed, it may start generating System-Checker Ads on every website that you visit. They may be customized according to your preferences, so it's not surprising that most of them may seem very interesting. However, keep in mind that each of the 'Ads by System-Checker' are developed and monitored by third-parties, which means that they may redirect you both to safe and suspicious websites.

From our report of Apr 2021 · not reviewed since

How can System-Checker hijack my computer?

In order to prevent System-Checker redirects, it's enough to ignore commercial messages that it may initiate.

That's because System Checker adware is also distributed via software packages. Generally speaking, the majority of adwares are distributed via other freewares and sharewares as 'optional downloads'. Therefore, in order to keep your computer safe, first of all you should avoid installing free programs without a purpose. If you decide to install one, make sure that you look for its official website or another reliable download source.

Besides, read EULA, Privacy Policy and other relevant information about it. Finally, opt for Advanced or Custom installation and carefully check everything step-by-step. If you notice a check box claiming that you agree to install System-Checker add-on on your computer, make sure that you opt out of it.

How to remove Ads by System

Uninstall first, then remove what stays behind, so the ads do not come back after a restart.

  1. Step 1: Uninstall Ads by System

    Open Settings > Apps > Installed apps in Windows 11, or Settings > Apps > Apps & features in Windows 10.

    Sort the list by install date and find Ads by System, then choose Uninstall from the three-dot menu next to it (in Windows 10, click the entry and then Uninstall).

    Remove anything else installed on the same day that you do not recognise, because such programs usually arrive together in one installer. If the uninstaller opens a browser page with an offer or a survey, close it: the program is removed either way.

    Full procedure with screenshots: Uninstall a program or app in Windows On uGetFix

  2. Step 2: Remove it from startup

    Whatever Ads by System installed usually starts with Windows.

    Open Task Manager with Ctrl + Shift + Esc, go to Startup apps in Windows 11 or the Startup tab in Windows 10, and disable what you do not know, starting with entries that have an empty Publisher column.

    Open file location on the right-click menu shows the file, which helps you decide and tells you what to delete later. Disabling is safe: if something you need stops working, switch it back on.

    Full procedure with screenshots: Stop apps from opening at startup On uGetFix

  3. Step 3: Delete the folders left behind

    What the uninstaller leaves behind is usually in the user folders. Open File Explorer, switch on View > Show > Hidden items (in Windows 10 View > Hidden items), and go through %LocalAppData%, %AppData%, %ProgramData% and the two Program Files folders.

    Sort by Date modified and delete folders that appeared together with the problem and belong to no program you use. Folders with random names that hold .exe, .dll, .js or .ps1 files are the strongest sign.

    Full procedure with screenshots: Remove what malware leaves behind in Windows

  4. Step 4: Reset the browser

    Finish the browser part with a reset, which puts the search engine, start page, new tab page and site permissions back to their defaults and switches extensions off. Chrome: Settings > Reset settings > Restore settings to their original defaults.

    Edge: Settings > Reset settings. Firefox: Help > More troubleshooting information > Refresh Firefox, which also removes its extensions. Your bookmarks and saved passwords are kept, and the menus are the same on Windows 11 and Windows 10.

    Chrome Settings page with the Reset settings section open
    Chrome on Windows 11: Settings > Reset settings.

    Full procedure with screenshots: Reset a browser and fix a hijacked search engine

  5. Step 5: Scan the PC, then run the offline scan

    Open Windows Security > Virus & threat protection > Scan options, run a Full scan and remove everything it finds. Then select Microsoft Defender Antivirus (offline scan) and click Scan now: the PC restarts and scans before Windows loads, which finds files that hide while Windows runs.

    Save your work first, because the offline scan takes about 15 minutes. Both scans are built into Windows 11 and Windows 10, and a second scanner from another vendor is a useful extra opinion.

    Windows Security Scan options with Microsoft Defender Antivirus offline scan selected
    Windows 11: Windows Security > Virus & threat protection > Scan options.

    Full procedure with screenshots: Run a Microsoft Defender Offline scan

Instructions for each browser and system

The detailed steps for every browser and system this guide covers. Open the one you use.

Uninstall from Windows

Uninstall from Windows 10/8:

  1. Type Control Panel into the Windows search box and open the result.
  2. Under Programs, select Uninstall a program.Uninstall from Windows 10/8

Uninstall from Windows 7/XP:

  1. Click on Windows Start > Control Panel (Windows XP users should click on Add/Remove Programs).
  2. In Control Panel, select Programs > Uninstall a program.Uninstall from Windows 7/XP

Remove the unwanted program:

  1. In the Programs and Features window, look for any recently installed suspicious entries, select them, and click Uninstall.
  2. If User Account Control appears, click Yes to confirm, then complete the removal.Uninstall the unwanted program from Windows
Remove from Google Chrome

Delete malicious extensions from Google Chrome:

  1. Open Google Chrome, click on the Menu (three vertical dots at the top-right corner) and select More tools > Extensions.
  2. In the newly opened window, you will see all the installed extensions. Uninstall all suspicious extensions related to the unwanted program by clicking Remove.Remove extensions from Chrome

Clear cache and web data from Chrome:

  1. Click on Menu and pick Settings.
  2. Under Privacy and security, select Clear browsing data.
  3. Select Browsing history, Cookies and other site data, as well as Cached images and files.
  4. Click Clear data.Clear cache and web data from Chrome

Change your homepage:

  1. Click menu and choose Settings.
  2. Look for a suspicious site in the On startup section.
  3. Click on Open a specific or set of pages and click on three dots to find the Remove option.

Reset Google Chrome:

If the previous methods did not help you, reset Google Chrome to eliminate all the unwanted components:

  1. Click on Menu and select Settings.
  2. In the Settings, scroll down and click Advanced.
  3. Scroll down and locate Reset and clean up section.
  4. Now click Restore settings to their original defaults.
  5. Confirm with Reset settings.Reset Chrome 2
Remove from Microsoft Edge

Delete unwanted extensions from MS Edge:

  1. Select Menu (three horizontal dots at the top-right of the browser window) and pick Extensions.
  2. From the list, pick the extension and click on the Gear icon.
  3. Click Remove.Remove extensions from Edge

Clear cookies and other browser data:

  1. Click on the Menu (three horizontal dots at the top-right of the browser window) and select Settings > Privacy, search, and services..
  2. Under Clear browsing data, pick Choose what to clear.
  3. Select Cookies and other site data and Cached images and files. (apart from passwords, although you might want to include Media licenses as well, if applicable) and click on Clear.Clear Edge browsing data

Restore new tab and homepage settings:

  1. Click the menu icon and choose Settings.
  2. Then find On startup section.
  3. Click Remove next to any suspicious startup page.

Reset MS Edge if the above steps did not work:

  1. Press on Ctrl + Shift + Esc to open Task Manager.
  2. Click on More details arrow at the bottom of the window.
  3. Select Details tab.
  4. Now scroll down and locate every entry with Microsoft Edge name in it. Right-click on each of them and select End Task to stop MS Edge from running.Reset MS Edge
Instructions for Chromium-based Edge

Delete extensions from MS Edge (Chromium):

  1. Open Edge and click select Settings > Extensions.
  2. Delete unwanted extensions by clicking Remove.Remove extensions from Chromium Edge

Clear cache and site data:

  1. Click on Menu and go to Settings.
  2. Select Privacy, search and services.
  3. Under Clear browsing data, pick Choose what to clear.
  4. Under Time range, pick All time.
  5. Select Clear now.Clear browser data from Chroum Edge

Reset Chromium-based MS Edge:

  1. Click on Menu and select Settings.
  2. On the left side, pick Reset settings.
  3. Select Restore settings to their default values.
  4. Confirm with Reset.
  5. This will disable extensions and reset startup pages but will not delete bookmarks, saved passwords, or browsing history.Reset Chromium Edge
Remove from Mozilla Firefox (FF)

Remove dangerous extensions:

  1. Open Mozilla Firefox browser and click on the Menu (three horizontal lines at the top-right of the window).
  2. Select Add-ons.
  3. In here, select the unwanted extension and click Remove.Remove extensions from Firefox

Reset the homepage:

  1. Click three horizontal lines at the top right corner to open the menu.
  2. Choose Settings.
  3. Under Home, set your preferred homepage and new tab settings.

Clear cookies and site data:

  1. Click Menu and pick Settings.
  2. Go to Privacy & Security section.
  3. Scroll down to locate Cookies and Site Data.
  4. Click on Clear Data...
  5. Select Cookies and Site Data and Temporary cached files and pages, then click Clear.Clear cookies and site data from Firefox

Reset Mozilla Firefox

If clearing the browser as explained above did not help, reset Mozilla Firefox:

  1. Open Mozilla Firefox browser and click the Menu.
  2. Go to Help and then choose Troubleshooting Information.Reset Firefox 1
  3. Under Give Firefox a tune up section, click on Refresh Firefox...
  4. Once the pop-up shows up, confirm the action by pressing on Refresh Firefox.Reset Firefox 2
Delete from Safari

Remove dangerous extensions:

  1. Open Safari, click Safari in the menu at the top-left of the screen, and select Preferences.
  2. Go to the Extensions tab, look for any suspicious entries, and click Uninstall to remove them.Remove extensions from Safari

Clear history and website data:

  1. Click Safari in the menu and pick Clear History.
  2. Set Clear to all history and confirm with Clear History.Clear history from Safari

Reset Safari:

  1. Click Safari in the menu and select Preferences > Advanced.
  2. Enable Show Develop menu in menu bar.
  3. From the menu bar, click Develop and select Empty Caches.Reset Safari
Delete from macOS

Remove the unwanted application:

  1. From the menu bar, select Go > Applications.
  2. In the Applications folder, look for any suspicious entries, then drag them to Trash (or right-click and pick Move to Trash).Uninstall from Mac

Delete leftover files and folders:

  1. Select Go > Go to Folder.
  2. Enter /Library/Application Support and remove any suspicious folders related to the unwanted program.
  3. Repeat the same check in the /Library/LaunchAgents and /Library/LaunchDaemons folders, deleting any suspicious entries.Delete leftover files from Mac
  4. Finally, empty the Trash to permanently remove the leftovers.

Do not let government spy on you

The government has many issues in regards to tracking users' data and spying on citizens, so you should take this into consideration and learn more about shady information gathering practices.

Avoid any unwanted government tracking or spying by going totally anonymous on the internet.

You can choose a different location when you go online and access any material you want without particular content restrictions. You can easily enjoy internet connection without any risks of being hacked by using VPN.

Control the information that can be accessed by government any other unwanted party and surf online without being spied on. Even if you are not involved in illegal activities or trust your selection of services, platforms, be suspicious for your own security and take precautionary measures by using the VPN service.

Backup files for the later use, in case of the malware attack

Computer users can suffer from data losses due to cyber infections or their own faulty doings.

Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact - you can set this process to be performed automatically.

When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use for the data restoration process.

From our report of Apr 2021 · not reviewed since

How to remove System-Checker virus?

System-Checker removal is not a difficult task.

Questions about Ads by System

What is Ads by System and why is it on my PC?

Ads by System is a program that was installed on the PC, most likely together with something else you downloaded. Free software sites and many installers add extra programs on setup pages with pre-ticked boxes, so the extra install looks like your choice even though nobody read the page.

Check the install date in Settings, Apps, Installed apps: the program you installed that day is the probable carrier. If you do not need Ads by System, uninstall it. If it belongs to your hardware or to a program you use, search its exact name and publisher first, because drivers and their tools can have unfamiliar names.

Ads by System will not uninstall. What can I do?

First restart the PC and try again, because the program may have been running and locked its own files. If the uninstaller is missing or fails, start Windows in Safe Mode, where most third-party programs do not start, and remove Ads by System from Installed apps there.

If it still refuses, delete its startup entry and its scheduled task, restart, and try once more. A program that actively prevents removal is behaving like malware, so finish with a Microsoft Defender offline scan. Avoid third-party uninstallers offered on search ads; several of them are unwanted programs themselves.

Is uninstalling Ads by System enough?

Often, but not always. Uninstalling Ads by System through Settings > Apps > Installed apps removes the main part. Ad-supported programs, however, frequently arrive together with others from the same installer, and some leave a scheduled task or a browser extension behind.

After uninstalling, sort the list of installed apps by date and look at what else appeared that day, check Task Manager > Startup apps, and open the extension page in every browser. A Microsoft Defender full scan at the end catches leftover files.

I let a "support technician" from an ad connect to my PC. What should I do?

Act quickly but calmly. Disconnect the PC from the internet first, so the connection ends. Uninstall the remote access tool they asked you to install and check Installed apps for anything else added during the call.

Run a Microsoft Defender full scan and offline scan. From another device, change your e-mail and banking passwords and sign out of all sessions.

If you paid by card, bank transfer or gift card, contact your bank or the card issuer immediately, and report the scam to the police. Do not answer if they call back.

My scan found nothing, but the ads continue. Why?

Because the source may not be a file a scanner looks for. Browser notifications are a permission stored in the browser, and many adware extensions are not flagged because they come from an official store.

Some ad-supported programs are only reported if you enable detection of potentially unwanted apps. So a clean scan does not mean the job is done. Check each browser's notification permissions and extension list by hand, and turn on Potentially unwanted app blocking in Windows Security before scanning again.

Can an adware pop-up infect my PC just by appearing?

No. A pop-up, a notification or a new tab is only a web page or a message. It cannot run programs on Windows by itself, provided the browser and Windows are up to date. Infection needs a step from you:

  • running a downloaded file
  • installing an extension
  • giving a stranger remote access

That is why scam pages work so hard to make you click. Close such pages with the tab's X or by closing the browser, not with buttons inside the page, which may start a download.

Why is my browser so slow since the ads started?

Each page now does extra work. An adware extension reads the page, decides where to put ads, loads them from ad servers and reports your visit, and that happens on every tab. Ad-supported programs add their own background activity.

Removing the extension or program usually makes the browser fast again at once. If it stays slow, open the browser's own task manager with Shift+Esc in Chrome or Edge and look for extensions using a lot of memory or processor time.

Did Ads by System collect my data?

Adware typically collects what it needs to choose ads:

  • the sites you visit
  • search terms
  • approximate location
  • browser and system details

Extensions with permission to read and change data on all websites can technically see everything on those pages, including forms. That is a privacy problem rather than proof of theft.

If you typed card details or passwords while it was active, changing the most important passwords is a reasonable precaution. Clearing cookies after removal ends the tracking sessions it may have started.

Will Fortect remove Ads by System?

Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.

For Ads by System, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.

Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.

Sources

  1. Google Chrome Help: Use notifications to get alerts (no longer online) (read October 7, 2026)
  2. FTC: How to recognize, remove and avoid malware (read October 7, 2026)
  3. Microsoft Learn: Microsoft Defender Offline (read October 7, 2026)
  4. Microsoft Learn: How Microsoft names malware (read October 7, 2026)

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