What is adware and how to remove it

Adware is software that displays advertisements on your device in the form of intrusive pop-ups, banners, and in-browser ads. Although it’s commonly classified as a type of malware, not all adware is equally harmful.

At its most benign, adware is usually unwanted and annoying, often bundled with free software without your knowledge, and designed to generate advertising revenue for its developers by flooding your screen with pop-ups or targeted ads.

More aggressive adware can slow down your device, hijack your browser, compromise your privacy, or even expose you to additional malware. And the threat is widespread: according to Zscaler, adware emerged as the top mobile threat, accounting for 69% of cases in 2025.

So, how does adware get onto your device, and how can you tell if it’s already there? We’ll explore the main types of adware, how they work, how to remove them, and how to prevent future infections.

The three types of adware

Adware generally falls into one of three categories: upfront adware, potentially unwanted applications or programs (PUAs/PUPs), and malicious adware.

Let’s take a closer look at each of the three types of adware and how they work:

Upfront adware

With upfront adware, the developer earns advertising revenue to help fund the app’s development and maintenance, while you get free access in return. This model is generally known as ad-supported software, and sometimes called legitimate adware.

Unlike deceptive forms of adware, legitimate ad-supported software is transparent about displaying advertisements. But that doesn't mean it's entirely risk-free. Some apps may track your activity to deliver targeted ads and share the information they collect with advertisers or other third parties, depending on their privacy practices. Frequent ads can also disrupt your experience, consume data, and affect device performance.

While legitimate adware is generally more of a trade-off than a security threat, it’s important to understand what you’re agreeing to. Before downloading free software, review its permissions and privacy policy to see what information it collects and how that data may be used.

Potentially unwanted applications (PUAs)

PUAs, also known as potentially unwanted programs (PUPs), are a common way adware ends up on your device without your clear consent. Often bundled with free software, these programs may display intrusive ads, redirect your browser to sponsored websites, or track your online activity. Unlike upfront adware, their presence and advertising behavior may not be clearly disclosed.

Once installed, PUAs can make everyday tasks frustrating. Persistent pop-ups may cover the content you're trying to read, interrupt your work, or force you to repeatedly close unwanted windows. Some programs may also hijack your browser, changing your homepage or default search engine without your permission.

PUAs can also affect your device's performance. Programs that run continuously in the background may consume processing power and memory, contributing to slower performance, reduced battery life, or an unresponsive browser.

More concerning is the potential impact on your privacy. Some adware-related PUAs track your online activity, collecting information about your searches, browsing habits, and interactions with advertisements. This data may be shared with advertisers or other third parties without your clear, informed consent.

Malicious adware

Malicious adware goes beyond displaying unwanted advertisements to actively threaten your device's security and personal information. Unlike legitimate ad-supported software or less harmful PUAs, malicious adware may steal sensitive data, compromise system settings, or expose your device to additional malware.

Here’s what malicious adware can do:

• Steal sensitive data: Some malicious adware collects browsing history, search queries, and sensitive information, potentially sharing or selling it to third parties, including data brokers.
• Expose you to malware: Malicious adware can serve as an attack vector, redirecting you to dangerous websites or downloading additional threats, including computer viruses and other malware.
• Enable financial theft: More aggressive variants may attempt to capture financial information, such as banking credentials or credit card details, putting your accounts and money at risk.
• Take control of browser settings: Some malicious adware can change your homepage, replace your default search engine, or redirect your browsing activity without permission. It may also resist removal by restoring unwanted settings.

One notorious example is Fireball adware, which researchers estimated had affected more than 250 million computers in 2017. Linked to a Chinese digital marketing agency, Fireball spread through bundled software downloads and hijacked browsers to redirect searches and generate advertising revenue.  Researchers also warned that its capabilities could potentially be used to download additional malicious software.

Although the terms sound similar, malicious adware and malvertising aren't the same thing. Adware is software installed on your device that displays unwanted ads, while malvertising involves using online advertisements to distribute malware, redirect users to malicious websites, or carry out scams.

How does adware work?

Once installed, adware can run in the background, displaying advertisements while you browse the web or use certain apps. It may trigger pop-ups, insert ads into webpages, open unwanted browser tabs, or change your browser settings to redirect you to sponsored websites. Some variants also track your browsing activity to deliver targeted advertisements.

Adware typically generates revenue for its developers through ad impressions, clicks, or redirects. While some ads promote legitimate products and services, others may lead to misleading offers, fraudulent websites, or scams, such as miracle weight-loss products and get-rich-quick schemes. The more ads you view or interact with, the more money the adware developer earns.

Common signs of adware on your devices

If you’re seeing a lot more ads than usual when browsing the web, you may have adware, especially if you’re repeatedly encountering intrusive pop-ups. However, there are also less obvious signs of an adware infection:

• Decreased system performance: Adware can significantly slow down your phone or computer, leading to longer load times and random crashes.
• Altered browser settings: Some adware can alter browser settings without your knowledge, primarily to allow for more ads to get through.
• New, unrecognized programs, apps, and toolbars: Adware can introduce programs, toolbars, and browser extensions on your device that you didn’t knowingly download. Uninstall any apps and add-ons you don’t recognize.
• Browser redirects: You may be redirected to malicious websites when trying to visit known, trusted sites.
• Connectivity interruptions: Adware can disrupt your internet connection, making browsing more difficult.
• Battery drain: Adware can drain battery life by constantly running in the background.
• Increased data usage: Adware may also create spikes in data usage because it’s always on.
• Excessive notifications: Adware can send you multiple pointless notifications, further slowing down device speed and distracting you.

Tips to prevent adware

The best way to deal with adware is to stop it from getting onto your device in the first place. A few smart browsing and download habits can make a big difference.

Here’s how to help keep unwanted adware out:

• Keep your software up to date: Ensure your apps, system drivers, operating system (OS), and other software are always updated to benefit from the latest security patches.
• Avoid visiting unsafe websites: Avoid suspicious websites and check for an HTTPS connection, but remember that encryption alone doesn't guarantee a site is safe. Malicious websites may attempt drive-by downloads that exploit security vulnerabilities to install unwanted software.
• Use ad-blockers: Install trusted ad-blocking software and browser extensions to help prevent malicious ads and pop-ups appearing on your screen.
• Keep it legal: Avoid pirated media and software, which may contain adware or other malware distributed by cybercriminals.
• Read terms and agreements: Many third-party apps are opt-out, requiring you to uncheck a box to avoid installing additional PUAs. Always understand what you’re installing before you proceed.
• Download apps from reputable sources: Use official app stores like the App Store and Google Play, which have strict security protocols.
• Click with caution: Be wary of suspicious links and attachments that can lead to adware, and learn how to identify a fake website before you engage with it.
• Use trusted security software: Reputable antivirus software like Norton 360 can help detect and remove adware and other potentially unwanted applications.

How to remove adware from your devices

There are two main ways to remove adware from your device. You can use a malware scanner to automatically detect and remove unwanted software, or remove it manually by uninstalling suspicious apps and browser extensions. The best approach depends on your device and the type of adware involved.

How to remove adware with antivirus

Trustworthy antivirus software can help detect and remove adware, PUAs, and other malicious programs. Follow these steps to scan your device and remove unwanted software:

1. Install trusted antivirus software: If you don't already have antivirus protection, download a reputable antivirus app from its official website or your device's app store.
2. Consider restarting in safe mode: If adware is interfering with your device or preventing security software from running, restarting in safe mode may help stop unwanted programs from launching automatically. This step is optional, and we'll explain how it works on different devices below.
3. Run a full system scan: Open your antivirus app and select a full or deep scan to check for adware and other potential threats. Follow the software's instructions, as some scans may need to run outside safe mode.
4. Review and remove detected threats: Once the scan finishes, review the results and select the recommended Remove, Quarantine, or Fix option, depending on your antivirus software.

How to remove adware on Android

Using Safe Mode is one of the most effective ways to manually remove mobile threats, such as adware, from an Android device. Here’s how to do it:

1. Hold the power button (or button combination) until the power off menu appears. Hold Power off until Safe mode appears, then tap it to confirm and restart in Safe mode. You should see Safe mode in the bottom corner of your screen after it reboots.

2. Adware can sometimes block removal by becoming a device administrator. To fix this, go to Settings > Security and privacy > Permission manager and check the permissions for your installed apps. Revoke any that look suspicious.

3. Next, open Settings and go to Apps. Make sure your filter is clear so all apps are visible.

4. Carefully review all of the apps on your device. If any seem unfamiliar or suspicious, uninstall them and then restart your phone.

Note that these steps for removing adware on Android may vary slightly depending on your specific Android device and OS version. In this article, we’re showing you how to do it on a Samsung Galaxy S26.

How to remove adware from iPhone

All iPhones run on Apple’s iOS, which regularly receives updates to protect devices from adware. But if you think your device has been compromised, follow these steps to remove unwanted programs:

1. Start on the Home Screen, then swipe left through all your Home Screen pages to open the App Library.

2. If you see any apps in the App Library you don’t recognize or don’t need anymore, long-press the app and select the Delete App option when prompted.

If you’re still seeing ads, it might not be adware after all. It’s a good idea to uninstall apps you no longer use or that seem suspicious, but you may also need to take extra steps to remove pop-up ads on your phone to minimize the number of ads you see while browsing.

How to remove adware from a Mac

To manually remove adware from your Mac, identify and uninstall suspicious or unfamiliar applications that could be serving you unwanted ads. Here’s how:

1. Open Spotlight Search and type in Activity Monitor. Double-click the app to open.

2. Look for any apps that are using a lot of resources or that you don’t recognize. Right-click the offending app, then click the X button and select Force Quit.

3. Open Finder, click Applications, then right-click the suspicious app and select Move to Trash.

4. Once you’ve cleared out all the suspicious apps, go to Trash and click the Empty button.

That should clear the unwanted adware from your Mac. You can also uninstall and reinstall browser apps to help ensure any browser-hijacking adware isn’t saved there.

How to remove adware from a PC

You can use a virus removal tool to help scan for and remove viruses and other known malware — like adware — from your PC. Or, you can manually uninstall a program you suspect to be adware. Here’s how to remove adware from a PC:

1. From the Windows Start menu, search for Control Panel and open it.

2. Under Programs, click Uninstall a program.

3. Review the list of programs and look for any unfamiliar apps. Right-click the app and choose Uninstall. Confirm by selecting Yes when prompted. If you get a second prompt to confirm, click Yes again.

Help stop malicious adware with help from Norton

Malicious adware can do more than bombard you with unwanted ads. It can invade your privacy, track your activity, and create opportunities for other threats to reach your device, making proactive protection especially important.

Norton 360 helps detect and block adware and other malware in real time, while protecting you from malicious websites, scams, and emerging threats. Get comprehensive protection that helps keep your device, data, and privacy safer from the threats hiding behind seemingly harmless software.

FAQs

Is adware really that bad?

Adware is usually more annoying than dangerous, especially when compared to other types of malware. But while adware may be benign, some types can still expose your device to dangerous malware or compromise your online privacy.

What’s the difference between adware and spyware?

Adware and spyware are both types of malware, which are usually downloaded without the user’s knowledge or consent. The crucial difference is that adware exists as a revenue generator. Spyware primarily tracks your online activity and mines your personal data.

How does adware affect computers?

The most obvious way adware affects computers is by increasing the number of ads you see while using your device. Some adware also slows computer performance, changes browser settings (typically to allow more ads), displays web pages differently (or incorrectly), or leads to further malware infections.

What can malicious adware do?

Beyond displaying intrusive ads, malicious adware may hijack your browser, track your online activity, collect sensitive information, slow down your device, or install unwanted applications. Some variants can also redirect you to dangerous websites or download additional malware, putting your privacy and security at risk.