Open4u Virus

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This page aims to help you remove Open4u. Our removal instructions work for Chrome, Firefox and Internet Explorer, as well as every version of Windows.


Open4u is a browser hijacking app, created to display sponsored advertisements and redirect prompts on every web page the users visit through their browser. Open4u can also promote different search engines, homepages, toolbars, and other browser components by replacing the existing ones with them.


The Open4u Virus will redirect your browser searches.

Open4u is a new representative of the browser hijacker category that usually displays multiple advertisements (such as pop-up messages, banners, text links, new tabs, box notifications, etc.) directly on the web browser’s screen during the browsing sessions. To ensure better control over the content that gets shown on the screen, the hijacker can typically install a search engine of its own and replace the homepage with one that automatically redirects to specific sponsored pages. No web browser is immune against being hijacked by an application like Open4u, therefore even web users who use well-known and safe browsers such as Chrome, Firefox, Edge, and Safari can experience the annoyance of the numerous advertisements on their screen and the imposed browser modifications.
This article, however, has been created in response to the growing number of web users who have been asking us how to deal with the different advertisements and the potentially unwanted browser changes that have been disturbing their web browsing activity. That’s why below we have published a removal guide with instructions that explain exactly how to remove Open4u and uninstall its changes.

Open4u virus on phone

A browser hijacker such as Open4u can become part of your system in many different ways. Sometimes, you may let it get installed when you visit a web page that prompts you to download some free applications. In other cases, you may get it installed when you download torrents from free file-sharing sites, or when you click on some spam message in your inbox and download its free attachment.

Among the diverse ways of browser hijacker distribution, however, the most commonly employed one is to bundle it into the software package of another free and attractive program, game, software optimizer, free audio or video player, etc.  Therefore, you should always read the EULA and check thoroughly the installers of any new programs in your system and especially the Advanced/Custom settings where programs like Open4u can often be found.

Can Open4u put your system in danger?

Browser Hijackers are generally harmless programs used for aggressive online advertising. Yet, the ads, banners, pop-ups and redirect links they display typically manage to irritate the end-users to such an extent that they consider such programs for some sort of redirect viruses and even put their name next to malware such as Ransomware and Trojans. However, in reality, programs like Open4u are not able to carry out the deceptive activities that a real Ransomware or a Trojan horse can perform.

Still, even though it is far from a virus, you might prefer to uninstall the browser hijacker and remove its ads due to a number of other reasons. For instance, such software can often interrupt your browsing sessions with irrelevant and annoying offers, promotions, coupons, notifications for different deals and similar commercial messages. And even if you try to put that disturbance aside, it will be hard to ignore the browser’s unresponsiveness and the sudden crashes that may take place every now and then due to system overloading with continuous page-redirecting and ad-generating processes.


Name Open4u
Type Browser Hijacker
Danger Level Medium (nowhere near threats like Ransomware, but still a security risk)
Symptoms A Browser Hijacker will typically start to redirect your web searches to pre-defined URLs and to fill your screen with sponsored ads.
Distribution Method Free software bundles may often contain Browser Hijackers inside their installation packages.
Detection Tool

Open4u Virus Removal

If you have a Windows virus, continue with the guide below.

If you have a Mac virus, please use our How to remove Ads on Mac guide.

If you have an Android virus, please use our Android Malware Removal guide.

If you have an iPhone virus, please use our iPhone Virus Removal guide


Some of the steps will likely require you to exit the page. Bookmark it for later reference.

Reboot in Safe Mode (use this guide if you don’t know how to do it).



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.

Press CTRL + SHIFT + ESC at the same time and go to the Processes Tab (the “Details” Tab on Win 8 and 10). Try to determine which processes are dangerous. 


Right click on each of them and select Open File Location. Then scan the files with our free online virus scanner:

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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

After you open their folder, end the processes that are infected, then delete their folders. 

Note: If you are sure something is part of the infection – delete it, even if the scanner doesn’t flag it. No anti-virus program can detect all infections. 


Hold together the Start Key and R. Type appwiz.cpl –> OK.


You are now in the Control Panel. Look for suspicious entries. Uninstall it/them.

Type msconfig in the search field and hit enter. A window will pop-up:


Startup —> Uncheck entries that have “Unknown” as Manufacturer or otherwise look suspicious.


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.

Hold the Start Key and R –  copy + paste the following and click OK:

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

A new file will open. If you are hacked, there will be a bunch of other IPs connected to you at the bottom. Look at the image below:

hosts_opt (1)

If there are suspicious IPs below “Localhost” – write to us in the comments.

Open the start menu and search for Network Connections (On Windows 10 you just write it after clicking the Windows button), press enter.

  1. Right-click on the Network Adapter you are using —> Properties —> Internet Protocol Version 4 (ICP/IP), click  Properties.
  2. The DNS line should be set to Obtain DNS server automatically. If it is not, set it yourself.
  3. Click on Advanced —> the DNS tab. Remove everything here (if there is something) —> OK.



  • After you complete this step, the threat will be gone from your browsers. Finish the next step as well or it may reappear on a system reboot.

Right click on the browser’s shortcut —> Properties.

NOTE: We are showing Google Chrome, but you can do this for Firefox and IE (or Edge).


Properties —–> Shortcut. In Target, remove everything after .exe.

ie9-10_512x512  Remove Open4u from Internet Explorer:

Open IE, click  IE GEAR —–> Manage Add-ons.

pic 3

Find the threat —> Disable. Go to IE GEAR —–> Internet Options —> change the URL to whatever you use (if hijacked) —> Apply.

firefox-512 Remove Open4u from Firefox:

Open Firefoxclick  mozilla menu  ——-> Add-ons —-> Extensions.

pic 6

Find the adware/malware —> Remove.
chrome-logo-transparent-backgroundRemove Open4u from Chrome:

Close Chrome. Navigate to:

 C:/Users/!!!!USER NAME!!!!/AppData/Local/Google/Chrome/User Data. There is a Folder called “Default” inside:

Rename the Folder to Backup Default

Rename it to Backup Default. Restart Chrome.


Type Regedit in the windows search field and press Enter.

Inside, press CTRL and F together and type the threat’s Name. Right click and delete any entries you find with a similar name. If they don’t show up this way, go manually to these directories and delete/uninstall them:

  • HKEY_CURRENT_USER—-Software—–Random Directory. It could be any one of them – ask us if you can’t discern which ones are malicious.
    HKEY_CURRENT_USER—-Software—Microsoft—-Windows—CurrentVersion—Run– Random
    HKEY_CURRENT_USER—-Software—Microsoft—Internet Explorer—-Main—- Random

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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