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How to remove CheckLetter adware from the operating system?

Also Known As: Ads by CheckLetter
Type: Mac Virus
Damage level: Medium

What is CheckLetter?

CheckLetter is a rogue app classified as adware. It also has browser hijacker qualities. Furthermore, due to the questionable techniques used to distribute software products of this type, they are also considered to be PUAs (Potentially Unwanted Applications).

CheckLetter adware

CheckLetter adware overview

Adware can display pop-ups, banners, coupons, and other intrusive advertisements on any visited website and/or different interfaces. They diminish the browsing experience by limiting webpage visibility and slowing down the browsing speed.

The delivered ads can be misleading, deceptive, and even dangerous. They promote various untrustworthy and even malicious sites. What is more, some intrusive adverts can be triggered (by being clicked on) to stealthily download/install software (e.g., PUAs).

Browser hijackers reassign browsers' homepage, default search engine, and new tab/window URLs to fake web searchers. Hence, every web search performed via the URL bar and new tab/window opened - redirect to the promoted address.

Fake search engines usually cannot provide search results, so they redirect to Google, Bing, Yahoo, and other genuine ones. Browser hijackers also use persistence-ensuring techniques to prevent users from recovering their browsers.

Adware and browser hijackers typically have data tracking abilities. They monitor browsing activity (URLs visited, pages viewed, search queries typed, etc.) and collect sensitive data extracted from it (IP addresses, personally identifiable details, etc.). The gathered information is then shared with and/or sold to third-parties.

In summary, the presence of unwanted apps on devices can lead to system infections, severe privacy issues, financial losses, and even identity theft.

Threat Summary:
Name Ads by CheckLetter
Threat Type Adware, Mac malware, Mac virus
Detection Names Avast (MacOS:Adload-AG [Adw]), Combo Cleaner (Gen:Variant.Adware.MAC.AdLoad.13), ESET-NOD32 (A Variant Of OSX/Adware.Synataeb.G), Kaspersky (Not-a-virus:HEUR:AdWare.OSX.Adload.j), Full List (VirusTotal)
Additional Information This application belongs to Adload malware family.
Symptoms Your Mac becomes slower than normal, you see unwanted pop-up ads, you are redirected to dubious websites.
Distribution methods Deceptive pop-up ads, free software installers (bundling), fake Flash Player installers, torrent file downloads.
Damage Internet browser tracking (potential privacy issues), display of unwanted ads, redirects to dubious websites, loss of private information.
Malware Removal (Mac)

To eliminate possible malware infections, scan your Mac with legitimate antivirus software. Our security researchers recommend using Combo Cleaner.
▼ Download Combo Cleaner for Mac
To use full-featured product, you have to purchase a license for Combo Cleaner. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Adware in general

AboutDynamicUpgradeSearchView, and ModeService are a few examples of adware. This software appears harmless and offers "handy" features, which rarely work. In fact, functionality and user safety are irrelevant for practically all PUAs, as their sole goal is to generate revenue for the developers.

How did CheckLetter install on my computer?

PUAs are spread using the "bundling" marketing tactic - packing regular programs with various additions. Rushed downloads/installations increase the risk of allowing bundled content into the device. Intrusive adverts proliferate PUAs as well. Once clicked on, the ads can execute scripts to download/install these apps without user permission. Some PUAs also have "official" promotional/download sites.

How to avoid installation of potentially unwanted applications?

It is advised to research software and only download from official/verified sources. Untrustworthy download channels, e.g., unofficial and free file-hosting websites, Peer-to-Peer sharing networks, etc. - commonly offer bundled content.

When downloading/installing, it is recommended to read terms, study available options, use the "Custom/Advanced" settings, and opt-out from all supplements. Intrusive advertisements appear legitimate, yet they redirect to unreliable and questionable sites (e.g., pornography, gambling, adult-dating, etc.).

In case of encounters with such ads and/or redirects, the device must be inspected and all suspicious applications and browser extensions/plug-ins detected - removed from it without delay. If your computer is already infected with CheckLetter, we recommend running a scan with Combo Cleaner Antivirus for macOS to automatically eliminate this adware.

Pop-up window displayed once CheckLetter adware's installation is over:

Pop-up displayed once CheckLetter installation is complete

CheckLetter adware's installation folder:

CheckLetter adware install folder

Instant automatic Mac malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of Mac malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner for Mac By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Quick menu:

Video showing how to remove CheckLetter adware using Combo Cleaner:

CheckLetter adware removal:

Remove CheckLetter-related potentially unwanted applications from your "Applications" folder:

mac browser hijacker removal from applications folder

Click the Finder icon. In the Finder window, select "Applications". In the applications folder, look for "MPlayerX","NicePlayer", or other suspicious applications and drag them to the Trash.

After removing the potentially unwanted application(s) that cause online ads, scan your Mac for any remaining unwanted components.

Remove ads by checkletter related files and folders:

Finder go to folder command

Click the Finder icon, from the menu bar. Choose Go, and click Go to Folder...

step1Check for adware-generated files in the /Library/LaunchAgents folder:

removing adware from launch agents folder step 1

In the Go to Folder... bar, type: /Library/LaunchAgents

removing adware from launch agents folder step 2
In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

step2Check for adware generated files in the /Library/Application Support folder:

removing adware from application support folder step 1

In the Go to Folder... bar, type: /Library/Application Support

removing adware from application support folder step 2
In the “Application Support” folder, look for any recently-added suspicious folders. For example, “MplayerX” or “NicePlayer”, and move these folders to the Trash.

step3Check for adware-generated files in the ~/Library/LaunchAgents folder:

removing adware from ~launch agents folder step 1


In the Go to Folder bar, type: ~/Library/LaunchAgents

removing adware from ~launch agents folder step 2

In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

step4Check for adware-generated files in the /Library/LaunchDaemons folder:

removing adware from launch daemons folder step 1
In the Go to Folder... bar, type: /Library/LaunchDaemons

removing adware from launch daemons folder step 2
In the “LaunchDaemons” folder, look for recently-added suspicious files. For example “com.aoudad.net-preferences.plist”, “com.myppes.net-preferences.plist”, "com.kuklorest.net-preferences.plist”, “com.avickUpd.plist”, etc., and move them to the Trash.

step 5 Scan your Mac with Combo Cleaner:

If you have followed all the steps in the correct order you Mac should be clean of infections. To be sure your system is not infected run a scan with Combo Cleaner Antivirus. Download it HERE. After downloading the file double click combocleaner.dmg installer, in the opened window drag and drop Combo Cleaner icon on top of the Applications icon. Now open your launchpad and click on the Combo Cleaner icon. Wait until Combo Cleaner updates it's virus definition database and click "Start Combo Scan" button.

scan-with-combo-cleaner-1

Combo Cleaner will scan your Mac for malware infections. If the antivirus scan displays "no threats found" - this means that you can continue with the removal guide, otherwise it's recommended to remove any found infections before continuing.

scan-with-combo-cleaner-2

After removing files and folders generated by the adware, continue to remove rogue extensions from your Internet browsers.

Ads by CheckLetter removal from Internet browsers:

safari browser iconRemove malicious extensions from Safari:

Remove ads by checkletter related Safari extensions:

safari browser preferences

Open Safari browser, from the menu bar, select "Safari" and click "Preferences...".

safari extensions window

In the preferences window, select "Extensions" and look for any recently-installed suspicious extensions. When located, click the "Uninstall" button next to it/them. Note that you can safely uninstall all extensions from your Safari browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Safari.

firefox browser iconRemove malicious plug-ins from Mozilla Firefox:

Remove ads by checkletter related Mozilla Firefox add-ons:

accessing mozilla firefox add-ons

Open your Mozilla Firefox browser. At the top right corner of the screen, click the "Open Menu" (three horizontal lines) button. From the opened menu, choose "Add-ons".

removing malicious add-ons from mozilla firefox

Choose the "Extensions" tab and look for any recently-installed suspicious add-ons. When located, click the "Remove" button next to it/them. Note that you can safely uninstall all extensions from your Mozilla Firefox browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Mozilla Firefox.

chrome-browser-iconRemove malicious extensions from Google Chrome:

Remove ads by checkletter related Google Chrome add-ons:

removing malicious google chrome extensions step 1

Open Google Chrome and click the "Chrome menu" (three horizontal lines) button located in the top-right corner of the browser window. From the drop-down menu, choose "More Tools" and select "Extensions".

removing malicious Google Chrome extensions step 2

In the "Extensions" window, look for any recently-installed suspicious add-ons. When located, click the "Trash" button next to it/them. Note that you can safely uninstall all extensions from your Google Chrome browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Google Chrome.

Frequently Asked Questions (FAQ)

What harm can adware cause?

Adware can negatively affect the browsing experience and system performance. Additionally, most adware-type apps can track data - which makes them a threat to user privacy. Furthermore, adware-delivered adverts can promote deceptive/malicious content that can cause other serious issues.

What does adware do?

Advertising-supported software or adware - is designed to run intrusive advertisement campaigns. In other words, this software can display various ads on any visited website and/or different interfaces.

How do adware developers generate revenue?

Adware generates revenue through affiliate programs by promoting sites, software, services, and similar. The developers of this software can earn commission from ad clicks, website visits, file downloads, product purchases, service subscriptions, etc.

Will Combo Cleaner remove CheckLetter adware?

Yes, Combo Cleaner is capable of scanning devices and eliminating installed adware-type applications. It is noteworthy that manual removal is not always a perfect solution. In some cases, even after the adware is eliminated - leftover files remain hiding in the system. Furthermore, such components may continue running and causing problems.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
Ads by CheckLetter QR code
Scan this QR code to have an easy access removal guide of Ads by CheckLetter on your mobile device.
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To use full-featured product, you have to purchase a license for Combo Cleaner. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.