How to avoid and remove potentially unwanted programs (PUPs)

Dodge toolbars, browser add-ons and other undesirables when installing free software

What are potentially unwanted programs?

We're sure you've experienced it – You download a piece of free software, then open your browser to discover a strange toolbar has been added, your default search provider has been changed, or your homepage has been hijacked. You've picked up a PUP, or potentially unwanted program.

These programs are often packed up in software installers – usually for freeware, but sometimes also in paid software. They usually affect your web browser, attempting to direct traffic through routes that will profit their creators. They can also harvest data on your browsing and shopping habits, which is then sold to advertisers.

How to avoid PUPs

Although undesirable, such programs aren't viruses as such, and may not be picked up by your regular security software. The best defence against them is care and attention.

Read each step of free software installers carefully

Uncheck the boxes beside programs, toolbars or other add-ons that you don't want to install

Always read each step of the installer carefully and uncheck any necessary boxes (PUPs are almost always opt-out rather than opt-in). If you're offered a choice between Recommended and Custom installations, always opt for Custom – it's usually hiding some unwanted browser add-ons. Unchecky can help here by unchecking all tickboxes in software installers, and warning you if you are about to install a PUP.

Sometimes, when you install free software, PUPs are part of the deal and you can't opt out. When faced with the program's terms of use it's tempting to just click 'Next', but it's worth taking the time to read them in case the program is going to bring some unwanted friends to the party. In that situation, the best course of action is to simply close the installer and look for another program that won't foist such programs on you.

Unchecky automatically unticks checkboxes in software installers

Unchecky automatically unticks checkboxes in software installers so you don't miss any

It might be worth seeking out a portable version of the software you want to use; by definition, portable programs don't have to be installed (they are usually supplied in a ZIP archive), so won't include an installer with bundled add-ons.

If you really want to err on the side of caution, you can install free software in a sandbox to prevent PUPs and malware meddling with your system files. You can do this using a virtual machine, which runs an operating system in a window on your desktop, effectively emulating a second PC – see our guide to creating a virtual machine with VMware.

How to remove PUPs

You've done your best to avoid it, but your browser has been hijacked by a rogue toolbar and your homepage has been changed. If your antivirus software doesn't pick up the culprit, and you can't remove it through the browser's plug-ins menu, try Malwarebytes Anti-Malware.

Delete PUPs with Malwarebytes Anti Malware

Malwarebytes Anti-Malware can scan your system for PUPs and remove them

It can run safely alongside your antivirus, and can be set to detect PUPs (and PUMs – potentially unwanted modifications), and treat them as malware by flagging them for deletion.

Have you come across any particularly pernicious PUPs? How did you eliminate them? Let us know in the comments below!