What Is a PUP (Potentially Unwanted Program)?

Far from cute and furry, PUPs can host dangerous and destructive viruses

A conceptual illustration of potentially unwanted programs (PUPs) destroying a laptop computer.

Theresa Chiechi / Lifewire 

When you download software, even from reputable sites, sometimes you get more than you bargained for. You probably don't even realize that, as you've downloaded the program you want, a few potentially unwanted programs otherwise known as PUPs hopped onto your computer as well.

PUPs can be innocent and helpful add-ons for the program you want. Conversely, they can include spyware, adware, Trojans, worms and all kinds of nasty malware. They can be found on any kind of device that can download a program or app.

What Is a PUP?

A PUP (potentially unwanted program) is any program that you do not specifically approve for download onto your computer. Sometimes the software maker decides to include them for helpful reasons. For example, a piece of software might come with a third-party installer to help ease installation.

This is considered legal in most cases because of the End User License Agreements (EULA) that come standard with software downloads. EULAs are often so long that most people skip past them to click the I Accept button. However, this language is usually where most software providers tuck in a line or two about bundled programs, which is the practice of including additional programs in with the download you do want.

You don't have to accept EULA agreements. Read the title above the fine print to be sure you only accepted a EULA for the program you wanted. You should still be able to decline the EULA and move forward with the installation. If a program won't let you install it without that agreement, think carefully about whether or not it is something you truly need.

What Is a PUP Virus?

A PUP virus refers to situations where this extra software is actually not a helpful program at all. Instead, it is a virus that typically takes the form of a tiny program bundled into the software you are downloading. Sometimes the software manufacturer knows about it; sometimes they don't. A PUP virus can come in the form of adware, spyware, Trojans, worms, and other malware.

How Does a PUP Virus Work?

Because these viruses can come in so many different forms, there is no single way it works. One might use your system's resources, another might steal passwords, a third might lock up your computer and require a ransom to release it. It could be a Trojan that hides in legitimate software like the Artemis virus. The possibilities are endless, really.

How Do I Know If I Have a PUP Virus?

The warnings will be as varied as the type of PUP you downloaded. You might be blocked from downloading games on sites like Steam, notice constant website redirects, experience the blue screen of death, see a ridiculous number of pop up ads on a site, find a new toolbar on your web browser, and more. The key point here is that you will start noticing unusual things happening on your computer, tablet, or smartphone.

How Did I Get This PUP or a PUP Virus?

Unwanted programs are typically found on freeware sites that let you download software free of charge but you can also get them when you click on suspicious links or pop up ads.

How Do I Remove a PUP?

Removal of a PUP will depend on whether or not it's a harmless program or a virus. In the case of a third-party installer that you no longer need, for example, you can simply remove the program from your computer. If the PUP is a virus, it's going to take a tougher approach.

  1. When the program is one that you spot and realize you don't need, you can simply uninstall it and any files relating to it. Both Windows and macOS have clear ways to uninstall apps you no longer want to use.

  2. If you suspect the PUP is a virus, the easiest approach is to let a good antivirus program do the work for you. In most cases, it's a good idea to use both antivirus and anti-malware software to remove these types of infections. Persistent malware infections can be annoying but you can conquer them.

  3. If the PUP virus you contracted is a browser hijacker, you need to remove suspicious add-ons and extensions from your browser. The process varies a little for removing extensions from Safari and disabling extensions in Chrome. In Chrome, you also have the option to use the Chrome Cleanup Tool.

  4. If the problem is on a mobile device, you may need to try different techniques to remove the virus from Android.

  5. If none of those steps solve the problem, you can use System Restore to return to an earlier point on your computer before you picked up the PUP virus. Be sure to pick a time period where you know you definitely didn't already have the virus on your computer. 

Always scan your computer with antivirus software after any removal attempts to ensure the threat is gone.

How Can I Avoid Downloading a PUP or PUP Virus Again?

There are a few key ways in which you can lower your chances of acquiring a PUP or being re-infected with PUP virus.

  • Stop PUPs from loading. Turn on the option to detect Potentially Unwanted Programs in your antivirus software. This will help you catch programs that are attempting to slide past you when you download otherwise legitimate programs.
  • Update your antivirus software and malware protection regularly. New virus definitions are released daily or more often. Only current protection can keep your PC informed on what to look for in regard to new viruses or other threats like the Pokki virus. 
  • Be careful when you download new programs. Always know the legitimacy of the source of the programs and apps you download. Some sites include add-ons that you don't need; that's where PUPs lurk.
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