Main Captcha Source Virus

7-day Free Trial w/Credit card, no charge upfront or if you cancel up to 2 days before expiration; Subscription price varies per region w/ auto renewal unless you timely cancel; notification before you are billed; 30-day money-back guarantee; Read full terms and more information about free remover.

*Source of claim SH can remove it.

Main Captcha Source

Main Captcha Source is an ad-generating piece of software that acts fairly aggressively within users browsing programs. Apps like Main Captcha Source override the settings of the main browser and are therefore known as ‘browser hijackers’.

Main Captcha Source
The Main Captcha Source virus will display pop up ads and messages

If you have landed this particular program on your computer, then you will pretty much know it instantly. Software of this type tends to immediately make changes to the Chrome, Firefox or whatever other browser you’re currently using. And these changes usually concern the homepage, the default search engine and often also certain browser elements, of which you may be seeing many new ones (e.g. toolbars, bookmarks, etc.)

The Main Captcha Source Virus

In addition to all of this, the Main Captcha Source virus tends to annoy users the most with the substantial increase in the amount of ads you see on your screen. For instance, you may start getting bombarded with all sorts of popups and box messages, regardless of the sites you visit all because of the Main Captcha Source virus. Frantically blinking banners may start rolling out and covering half the screen, while colorful links start littering your favorite blog or news site.

These are all the common effects of software like Main Captcha Source, Bestcaptcharesolver, iStart Search Bar. And the reason for this is that the main purpose of browser hijackers is to generate profit for their developers via paid ads. This is made possible thanks to very popular online business models such as Pay Per View and Pay Per Click, of which you’ve no doubt heard before.

And while there’s nothing inherently wrong with these practices, it’s the fact that they are unwelcome, uncalled for and utterly uninvited that makes them a problem.

For instance, we’re quite certain that you never asked to be spammed with web ads. And for that matter, you probably didn’t want to install Main Captcha Source on your machine either.

The installation of software applications of this kind usually occurs with the help of a sneaky technique known as program bundling. As part of it, developers add components like adware, browser hijackers and similar pieces to the installation manager of various types of software that are generally always distributed for free.

For example, you may have recently installed a system optimization tool or file converter. And in most cases, that program came from some questionable file-sharing platform or similarly unreliable source.

If so, then you probably also ran the automatic (default) setup of the software and didn’t bother to read through any of the steps. If, however, you had opted for the slightly more detailed custom (also often labeled advanced) setup, then you would have had the opportunity to check for any added installs such as Main Captcha Source.

Furthermore, in these cases users often even have the option to exclude these additional components from the installation process. And that in turn, would have saved you the time and effort of having to look for removal solutions for this mysterious software piece that you didn’t even recall installing.

This is a good tip to keep in mind for the future, also because it may potentially protect you from far more serious issues like ransomware viruses and other malware. In fact, removing Main Captcha Source is also a step towards protecting yourself from viruses, because there’s no telling what kind of content the hijacker may expose you to.


NameMain Captcha Source
TypeBrowser Hijacker
Detection Tool

*Source of claim SH can remove it.

Remove Main Captcha Source Virus

The five instructions listed below offer you a quick way to remove Main Captcha Source from the browser’s list of Extensions where it is most likely that it has nestled. We recommend that you give them a try and see if that resolves the issue before you dig into the instructions of the step-by-step removal guide under them:

  1. With the hijacked browser open, tap on its Settings icon.
  2. Next, from Settings select More Tools/ Add-ons and click on it. 
  3. Then, click on the Extensions tab (located on the left) and open it.
  4. Search for any Main Captcha Source-related entries in the list and remove them.
  5. If there are other questionable extensions that you don’t want, remove them as well.

If you still experience browsing disturbance caused by Main Captcha Source after you complete the instructions above, follow the detailed guide below to uninstall the hijacker completely:


Bookmark this page and then reboot the computer in Safe Mode by using the instructions from this detailed guide.



*Source of claim SH can remove it.

When the computer reboots in Safe Mode, press together the CTRL, SHIFT, and ESC keyboard keys and click the Processes Tab (it is called “Details” Tab on Win 8 and 10). Search for processes that seem to have a relation to Main Captcha Source in the list, and when you find such a process, right-click it and click on Open File Location.


Then, run a virus scan of the files found in that location with the help of the free online virus scanner below:

Each file will be scanned with up to 64 antivirus programs to ensure maximum accuracy
This scanner is free and will always remain free for our website's users.
This file is not matched with any known malware in the database. You can either do a full real-time scan of the file or skip it to upload a new file. Doing a full scan with 64 antivirus programs can take up to 3-4 minutes per file.
Drag and Drop File Here To Scan
Drag and Drop File Here To Scan
Analyzing 0 s
Each file will be scanned with up to 64 antivirus programs to ensure maximum accuracy
    This scanner is based on VirusTotal's API. By submitting data to it, you agree to their Terms of Service and Privacy Policy, and to the sharing of your sample submission with the security community. Please do not submit files with personal information if you do not want them to be shared.

    End the questionable processes by going to the Processes tab in case the scanned files turn out to be malicious. Also, make sure to delete the harmful files from their File Location along with the folders that contain them. 


    Type appwiz.cpl in the Windows search field and hit the Enter keyboard key.  This will get you inside the Control Panel. Once in, search for entries related to  Main Captcha Source in the list of programs that are installed on your computer and if you find such entries, highlight them and select Uninstall from the options at the top.

    After that, go to the windows search field and type msconfig. Hit the Enter key and System Configurations will open on the screen: 


    Click the Startup tab and remove the checkmark for any entries that seem to be linked to Main Captcha Source or have an “Unknown” Manufacturer. After that click the Ok button and go to the next step.


    *Source of claim SH can remove it.

    Use the windows search field to type Network Connections and select it. After that, go to your currently used Network Adapter and right-click on it. Then, tap on Properties. In the Properties window, find Internet Protocol Version 4 (ICP/IP) and tap on it, then click the Properties button at the bottom. Check ifObtain DNS server automatically” is selected (or select it yourself if it is not) and then click on Advanced. Go to the DNS tab and remove everything that is written in the DNS server addresses field. To save your changes, click OK and move to the next step.



    Main Captcha Source may have added entries in the Registry that can help it reinstall on your system after reboot. To prevent that, you need to search the Registry for these entries and remove them. For that, go to the windows search field,  type Regedit and press Enter

    The Registry Editor will open. Once in it, press CTRL and F keyboard keys together and type the Name of the browser hijacker in the Find dialog box that appears on the screen. Click on Find Next and delete the found results by right-clicking on them. After that go manually to the following directories and delete them:

    • HKEY_CURRENT_USER—-Software—–Random Directory
    • HKEY_CURRENT_USER—-Software—Microsoft—-Windows—CurrentVersion—Run– Random
    • HKEY_CURRENT_USER—-Software—Microsoft—Internet Explorer—-Main—- Random

    One last thing that is highly recommended is to check your system for signs of hacking. To do that, press the Start and R keyboard keys together and copy the command listed below in the Run box that opens on the screen:

    notepad %windir%/system32/Drivers/etc/hosts

    Hit the Enter key after your paste the command and you will find yourself inside the Hosts file on your computer. In that file, find Localhost and search for questionable IPs under it.  If you see any (see the image below), please write to us in the comments section below this article.

    hosts_opt (1)


    The instructions below are aimed at helping you remove Main Captcha Source from your hijacked browser. Make sure you repeat them carefully, otherwise, the browser hijacker may install itself again when you reboot the computer the next time.

    NOTE: In the instructions that follow, we are using Google Chrome as an example. However,  the same steps can successfully be applied for Firefox and IE (or Edge), as well as other affected browsers.

    Right-click on the browser’s shortcut icon and tap on Properties.


    Once in the Properties window, click on the Shortcut tab. Go to Target and remove everything that has been added after .exe:

    Browser Hijacker Removal Instructions

    Then, click OK to save the changes.

    Next, close Google Chrome and go here:

     C:/Users/!!!!USER NAME!!!!/AppData/Local/Google/Chrome/User Data. You should search for a folder called “Default” in that location. When you find it, select it.

    Rename the Folder to Backup Default

    Then, right-click on that folder and change its name to Backup Default. Finally, restart Chrome.

    To make things easier for users who are using other browsers and to avoid any confusion, here we explain how to remove Main Captcha Source from Internet Explorer and Mozilla Firefox:

    ie9-10_512x512  Remove Main Captcha Source from Internet Explorer:

    Open Internet Explorer and head to the top right corner where the gear icon  IE GEAR is found. Click it and select Manage Add-ons from the available options.

    pic 3

    Once in the Add-ons list,  search for Main Captcha Source and Disable it.

    Then, go to the gear icon IE GEAR again and tap on Internet Options. Main Captcha Source may have changed your homepage address to a sponsored one. If that is the case, remove that address and set a homepage URL of your choice. Click on Apply and close the window.

    firefox-512 Remove Main Captcha Source from Firefox:

    Launch Firefox and click on the menu icon  mozilla menu. Navigate to Add-ons >>> Extensions. Then, search for Main Captcha Source in the Extensions list and remove it.

    pic 6

    If Main Captcha Source doesn’t want to get completely removed from your computer after you complete all the steps above, then it is best to scan the system with the recommended professional software and follow the steps suggested there.


    About the author


    Violet George

    Violet is an active writer with a passion for all things cyber security. She enjoys helping victims of computer virus infections remove them and successfully deal with the aftermath of the attacks. But most importantly, Violet makes it her priority to spend time educating people on privacy issues and maintaining the safety of their computers. It is her firm belief that by spreading this information, she can empower web users to effectively protect their personal data and their devices from hackers and cybercriminals.

    Leave a Comment

    We are here to help! Use SpyHunter to remove malware in under 15 minutes.

    Not Your OS? Download for Windows® and Mac®.

    * See Free Trial offer details and alternative Free offer here.

    ** SpyHunter Pro receives additional removal definitions and manual fixes through its HelpDesk in cases where they are needed.

    Spyware Helpdesk 1