How to Remove We Know AC Virus (Mac Guide) Dec. 2019 Update

Parasite may reinstall itself multiple times if you don't delete its core files. We recommend downloading SpyHunter to scan for malicious programs installed with it. This may save you hours and cut down your time to about 15 minutes. 

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More information on SpyHunter, steps to uninstallEULAThreat Assessment Criteria, and Privacy Policy.

We Know AC

If ads, banners, flashy pop-ups and intrusive page-redirects are disrupting every single browsing session that you start and if the browser that you typically use has had a number of changes imposed on it without you having agreed to them, then know that the most likely source of this intrusiveness is a browser hijacker. There are many thousands of hijackers on the Internet and pretty much every day new ones get made. However, in this specific post, we will focus on one called We Know AC – it is a new hijacker that is currently on the browsers of many users. Unlike regular add-ons for browsers, hijackers like this one are able to get attached to all kinds of browsers, Safari, Firefox and Chrome being the most commonly target ones.

We Know AC Browser Redirect

Once a hijacker is installed inside the browser, certain changes in the search engine, the addresses for the homepage and the new-tab page as well as in the toolbar are likely to occur. The purpose of those changes imposed by the hijacker is to make the advertising campaign conducted by it more effective. For instance, the new search engine added by the hijacker will likely favor and promote sites and pages that the hijacker itself is trying to promote. The new homepage will also probably be some web address that is supposed to get advertised by We Know AC or that shows a lot of ads on your screen. The situation with the toolbar may be similar. All in all, you can expect a lot of disturbance caused by a constant generation and display of annoying commercial messages all over your screen if you have the We Know AC Virus hijacker inside your computer. We may have some good news for you, though. The instructions included in the removal guide down below as well as the highly effective removal tool are both perfect options for uninstalling We Know AC and removing anything that it may have added to your browser.

Security concerns

The safety of your computer is unlikely to get directly threatened by We Know AC Virus since this is not a virus, a Trojan or a Ransomware infection – it is nothing more than an advertising tool that seeks to make money through its aggressive ads. These same ads, however, may indeed be unsafe in some occasions if they are linked with shady and hazardous sites and pages. It is, therefore, better to stay away from them and not click on them. Otherwise, you may indeed put your computer at risk of getting attacked by a nasty virus or another malware threat like a Ransomware, a Trojan or a Rootkit. You really don’t need that kind of stuff in your computer which is why it’s always best if you keep a safe distance from the adverts. Of course, doing that would be much easier if there are simply no intrusive ads in your browser which brings us back to the importance of quickly removing the hijacker responsible for them from your computer. In that way, you will greatly reduce the risk of exposing your machine to any dangerous and harmful malware.


Name We Know AC
Type  Browser Hijacker
Danger Level Medium (nowhere near threats like Ransomware, but still a security risk)
Symptoms  Usually, a hijacker will not try to hide its presence – the ads and the nagging changes to the browser are likely to give away the unwanted app.
Distribution Method Bundling hijacker apps with other program’s installers is how this type of unwanted software usually gets distributed.
Detection Tool

Remove We Know AC Virus


We get asked this a lot, so we are putting it here: Removing parasite manually may take hours and damage your system in the process. We recommend downloading SpyHunter to see if it can detect parasite files for you.

The first thing you need to do is to Quit Safari (if it is opened). If you have trouble closing it normally, you may need to Force Quit Safari:

You can choose the Apple menu and click on Force Quit.

Alternatively you can simultaneously press (the Command key situated next to the space bar), Option (the key right next to it) and Escape (the key located at the upper left corner of your keyboard).

If you have done it right a dialog box titled Force Quit Applications will open up.

In this new dialog window select Safari, then press the Force Quit button, then confirm with Force Quit again.

Close the dialog box/window.



To remove parasite on your own, you may have to meddle with system files and registries. If you were to do this, you need to be extremely careful, because you may damage your system.

If you want to avoid the risk, we recommend downloading SpyHunter
a professional malware removal tool.

More information on SpyHunter, steps to uninstallEULAThreat Assessment Criteria, and Privacy Policy.

Start Activity Monitor by opening up Finder, then proceed to activity-monitor

Once there, look at all the processes: if you believe any of them are hijacking your results, or are part of the problem, highlight the process with your mouse, then click the “i” button at the top. This will open up the following box:


Now click on Sample at the bottom:


Do this for all processes you believe are part of the threat, and run any suspicious files in our online virus scanner, then delete the malicious files:

Drag and Drop Files Here to Scan
Maximum file size: 128MB.

This scanner is free and will always remain free for our website's users. You can find its full-page version at:

Scan Results

Virus Scanner Result


The next step is to safely launch Safari again. Press and hold the Shift key while relaunching Safari. This will prevent Safari’s previously opened pages from loading again. Once Safari is opened up, you can release the Shift key.

On the off chance that you are still having trouble with scripts interrupting the closing of unwanted pages in Safari, you may need to take some additional measures.

First, Force Quit Safari again.

Now if you are using a Wi-Fi connection turn it off by selecting Wi-Fi off in you Mac’s Menu. If you are using a cable internet (Ethernet connection), disconnect the Ethernet cable.


Re-Launch Safari but don’t forget to press and hold the Shift button while doing it, so no previous pages can be opened up. Now, Click on Preferences in the Safari menu,

Preferences in Safari

and then again on the Extensions tab,

extensions in safari

Select and Uninstall any extensions that you don’t recognize by clicking on the Uninstall button. If you are not sure and don’t want to take any risks you can safely uninstall all extensions, none are required for normal system operation.

The threat has likely infected all of your browsers. The instructions below need to be applied for all browsers you are using.

Again select Preferences in the Safari Menu, but this time click on the Privacy tab,
Privacy in Safari

Now click on Remove All Website Data, confirm with Remove Now. Keep in mind that after you do this all stored website data will be deleted. You will need to sign-in again for all websites that require any form of authentication.

Still in the Preferences menu, hit the General tab

General Tab in Safari

Check if your Homepage is the one you have selected, if not change it to whatever you prefer.
Default Home Page

Select the History menu this time, and click on Clear History. This way you will prevent accidentally opening a problematic web page again.

firefox-512 How to Remove We Know AC From Firefox in OSX:

Open Firefoxclick on mozilla menu (top right) ——-> Add-onsHit Extensions next.

pic 6

The problem should be lurking somewhere around here –  Remove it. Then Refresh Your Firefox Settings.

chrome-logo-transparent-backgroundHow to Remove We Know AC From Chrome in OSX:

 Start Chrome, click chrome menu icon —–>More Tools —–> Extensions. There,  find the malware and  select  chrome-trash-icon.

pic 8

 Click chrome menu icon again, and proceed to Settings —> Search, the fourth tab, select Manage Search Engines.  Delete everything but the search engines you normally use. After that Reset Your Chrome Settings.

If the guide doesn’t help, download the anti-virus program we recommended or try our free online virus scanner. Also, you can always ask us in the comments for help!

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