PUABundler:Win32/Fusioncore Removal Guide
Win32/Fusioncore launches a lot of ads and unwanted programs on your computer.

PUABundler:Win32/FusionCore is a designation that Microsoft Defender Antivirus uses to detect and remove potentially unwanted programs (PUP) that are spread by bundling technology. FusionCore is not a stand-alone program, it is a piece of code that can install various unwanted elements such as adware, toolbars or browser extensions on your computer. Let me show you why it is dangerous and how to remove it.

What is PUABundler:Win32/FusionCore?

PUABundler:Win32/FusionCore is the detection name for a tool used for bundling additional applications with the main one. Initially, it was used to make the monetization of free software easier. But, nowadays it is mostly used for spreading unwanted software like adware, browser plug-ins, and pseudo-effective apps.

If you see the detection of PUABundler:Win32/FusionCore, it means that a software installer you’ve downloaded is infused with this bundler. Although it is not highly dangerous, having it running in the system is not desirable, and can end up with malware injection. Because of this, and also due to the hidden information about such installation methods, software bundling is considered an unwanted practice.

Is PUABundler:Win32/Fusioncore a false detection?

There is always a possibility for an antivirus detection to be false. Win32/Fusion core is not an exclusion, and it is particularly known to pop up on Android emulators. A particular apps users complain to have problems with is Nox APP Player.

Nox app player FusionCore
Reddit post with complaints about the emulator software being detected as FusionCore

It is not clear whether the app is 100% trustworthy or not. Some users suppose that this detection is due to the way the emulator displays ads. However, the detection itself is related to the operational file, i.e. there can barely be any code corresponding to the FusionCore description.

Win32/FusionCore Threat Analysis

The Win32/FusionCore operates in a unique way as it does not cause direct harm to the system. When executed, it installs additional software without the user’s consent, leading to unwanted changes in system settings or behavior. The symptoms of PUABundler:Win32/FusionCore infection I’ve encountered during the research include:

  • A significant increase in the number of pop-ups and banners that appear when browsing the Internet. These ads began appearing on websites where they were previously absent, disrupting the experience. Such a change is typical for adware activity.
Pop-up ads
Examples of unwanted pop-up advertisements
  • Unwanted software brought by Win32/FusionCore has permanently changed the browser homepage and default search engine settings. We found that the browser now opens to a different homepage or that search queries are redirected through unfamiliar search engines.
  • The system’s performance and Internet connection bandwidth become noticeably worse due to the large number of junk apps running on it. This is to be expected on a test system that I set up to correspond a weak computer build.
  • Win32/FusionCore itself made unauthorized changes to system settings. In particular, it modified the Windows registry and changed security settings.

How to Remove PUABundler:Win32/FusionCore?

Removing PUABundler:Win32/FusionCore from an infected system requires a comprehensive approach. Here are the steps to effectively remove Bundler FusionCore:


  1. Run a full system scan with a reliable antivirus software. We highly recommend Gridinsoft Anti-Malware. It can easily detect and remove PUABundler:Win32/FusionCore and related threats.
  2. Reset your browser settings. You can either do this manually through your browser settings or use GridinSoft Anti-Malware to do it for you. With the program, you can reset all your web browsers in just a few clicks, saving you a significant amount of time.
  3. It is important to use caution when downloading and installing programs from the Internet to prevent further infection. Always choose official or trusted sources and avoid unreliable or suspicious sites. In addition, choose selective or advanced installation mode whenever possible and avoid any additional or recommended components that could potentially contain PUPs.

By Stephanie Adlam

I write about how to make your Internet browsing comfortable and safe. The modern digital world is worth being a part of, and I want to show you how to do it properly.

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