Ontology.dll Trojan Removal (Feb. 2019 Update)

This page aims to help you remove Ontology.dll Trojan. Our removal instructions work for every version of Windows.

Ontology.dll is a legitimate Nvidia file. However often times there’s an error linked to this file that leads to users searching for a download link to Ontology.dll. This in turn leads to a massive infections with a Trojan Horse virus. This article is dedicated to the removal of just this – Ontology.dll Trojan.

Trojans are a terrible threat that we all have at one point or another heard of. They’re insidious, incredibly malicious and easily the most recognizable name of all viruses out there. So, naturally, you’d be pretty freaked out to find out that your computer has somehow gotten infected by one. And that would be the subject of today’s article – a Trojan horse virus called Ontology.dll that appears to be infecting quite a number of users as we speak. We have received reports about this virus, some more panicked than others, and frankly people are just asking for a working solution to saving their computers from Ontology.dll. So, here we are and we are happy to provide those of you who need it with a removal guide. The removal guide contains detailed instructions on how to locate and delete the malware with all its related files, so be sure to carefully read and follow the steps as you reach them. But for the moment, please finish reading this article for some perspective on what this current infection entails.

How harmful can Ontology.dll be to my system?

Well, the short answer to that question would be: very. Trojans are among the most dangerous malicious threats out there. But it doesn’t necessarily have to mean that you will need to kiss your system and files goodbye or that your life will be ruined as a result of this infection. Sometimes, the tasks of viruses of this type can be less harmful than others and if discovered on time, you might be able to avoid most of the damage they would have otherwise been capable to do. Speaking of discovering, Trojan horse viruses are notorious for their stealth. Therefore, it’s already great news that you even managed to detect Ontology.dll. This is also what makes them so invaluable to hackers around the globe.

Ontology.dll Trojan Removal



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).



Press CTRL + SHIFT + ESC at the same time and go to the Processes Tab. 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:

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

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. If you see a screen like this when you click Uninstall, choose NO:



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.

  • Remember this step – if you have reason to believe a bigger threat (like ransomware) is on your PC, check everything here.

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.


Type Regedit in the windows search field and press Enter.

Once inside, press CTRL and F together and type the virus’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


But besides that, they’re also a very precious asset because of their versatility and ability to execute a wider range of malicious actions than any other malware group. For this very reason we can’t exactly tell you what Ontology.dll is up to on your PC. But we can give you an idea of what it might be by outlining some of its most common usages. One of them is theft, and this can be theft of particular files from your computer, information that you put in, correspondence with other people, etc. The hackers could also be seeking to obtain financial details from you in order to get hold of your money – completely not uncommon. Another very common usage is resource exploitation. A Trojan could be inserted in your system for the purpose of using its resources for cryptocurrency mining, for example. Alternatively, your PC could be involved in a botnet for the purpose of distributing spam.

Ontology.dll could also be used as a means of spying on you in a number of different ways. Your keystrokes can be logged, your screen can be shared with the hackers without your knowledge, your mic and webcam can be tapped into. There’s a variety of possibilities for the criminals behind the virus to keep tabs on you and it’s very unsettling, to say the least. Other possible usages include distributing other malware, like ransomware for example. In addition, Ontology.dll could be programmed to destroy certain files or even format your disks and drives, wiping them clean of any information at all.

But regardless of the purpose of this particular infection, you now have the necessary tools to have it removed from your system. You should also take equally serious measures to ensure that your PC is protected from such malware in the future. And you can start by installing a reliable antivirus program or updating the one you already have. Be sure to keep an eye out for new updates that become available for your OS and manually install them, so that there are no vulnerabilities a Trojan or other virus could exploit. And last but not least, be especially careful when browsing the web. Choose the content you interact with carefully and avoid anything that appear sketchy or otherwise suspicious. You can save yourself a great deal of trouble by simply being conscious of all the dangers that are out there.


Name Ontology.dll
Type Trojan
Danger Level High (Trojans are often used as a backdoor for Ransomware)
Symptoms Trojans are notoriously stealthy and rarely, if ever, exhibit any symptoms
Distribution Method Malvertisements, spam messages, infected downloadable content, drive-by downloads, etc.
Detection Tool

Keep in mind, SpyHunter’s malware detection tool is free. To remove the infection, you’ll need to purchase the full version.
More information about SpyHunter and steps to uninstall.

If the guide didn’t help you, download the anti-virus program we recommended or ask us in the comments for guidance!

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