Lesson 5 of 7

Installing, switching and removing antivirus safely

If you have decided to install a product, or to remove one, the way you do it matters. This lesson walks through each situation step by step, so that you end up with one working product rather than two half-working ones.

Getting software from the right source

Criminals know that people go looking for security software, and some create fake download pages or advertisements that imitate well-known products. The software offered on those pages may itself be harmful. The safest habit is simple: get security software only from the vendor's own website or from your device's official app store.

• Type the vendor's web address yourself, or use a bookmark you created earlier, rather than following a link in an unexpected email or pop-up.
• Check the address bar carefully before downloading. Look-alike addresses often add a word or swap a letter.
• On a phone, install from the Google Play Store or Apple App Store, and check that the listed developer matches the company you expect.
• Be cautious with "download" buttons inside advertisements on other websites. They may lead somewhere else entirely.

Links on this site go to vendors' websites, not to downloads. We do not host or distribute any software.

Why only one product should be active

Two antivirus programs running at the same time can each try to inspect the same files as they are opened. The result can be a slow computer, programs that will not start, or, at worst, each product getting in the way of the other. Vendors generally advise against running two real-time products together.

On Windows, as mentioned in lesson two, Microsoft Defender Antivirus normally steps aside when another antivirus product is installed and registered with Windows Security. Microsoft explains this on its page about compatibility with other security products. Problems more often arise when two third-party products are installed together, or when an old product is only partly removed.

Installing a new product on Windows

1. Check you have what you need. Make sure you know the account details you will use with the vendor, and that your computer meets the vendor's system requirements.
2. Remove any other third-party antivirus first. The next section explains how. You do not need to remove Microsoft Defender Antivirus; it is part of Windows.
3. Download the installer from the vendor's own website. Save it, then open it from your Downloads folder.
4. Read each installation screen. Look for boxes, already ticked, offering extra software or browser changes. Untick anything you did not intend to install.
5. Let the product update. Most products download their latest protection data straight after installation. Leave the computer connected to the internet until that finishes.
6. Confirm Windows sees it. Open Windows Security and choose Virus & threat protection. The new product should be listed as the active provider.

Installing on a Mac

1. Download the product from the vendor's own website or the Mac App Store.
2. When you open the installer, macOS may ask for permission for parts of the product to run. Read each request; security products usually need wide access to do their job, but the request should match what the vendor describes.
3. Open System Settings, then Privacy & Security, and check any items the installer asked you to approve.
4. Keep macOS updates switched on. Installing a separate product does not replace them.

Removing an old product properly

Removing security software is not always as simple as deleting an app. Because these products install themselves deeply so they can protect the system, they often need a proper uninstall process.

On Windows

1. Open Settings, then Apps, then Installed apps.
2. Find the product, choose the three-dot menu next to it, and select Uninstall.
3. Follow the product's own uninstall screens. Some will ask you to confirm more than once, or offer a discount to stay. You can decline.
4. Restart the computer when asked.
5. If the product still appears in Windows Security afterwards, look on the vendor's support website for a removal tool. Many vendors publish one for exactly this situation.
6. Open Windows Security again and check that an antivirus provider is active, whether that is your new product or Microsoft Defender Antivirus.

On a Mac

Some Mac security products include their own uninstaller, often found inside the product's folder in Applications or in its menu. Use that rather than dragging the app to the Bin, so that background components are removed too. If in doubt, the vendor's support pages will say which method to use.

On a phone

Uninstall the app in the usual way. If the app was given device administrator rights on Android, you may need to remove those first in the security settings before the phone lets you uninstall it.

Checking everything after a change

Whether you added, switched or removed a product, take two minutes to confirm the result.

• Exactly one antivirus product is shown as active on each computer.
• The active product shows that its protection is up to date.
• Operating system updates are still switched on.
• No unexpected browser extensions or toolbars appeared during installation.
• If you cancelled a subscription, you have the vendor's confirmation saved somewhere you can find it.

Setting up a new computer

A new laptop is a good moment to make these decisions calmly. Some computers arrive with a trial security product already installed. You are under no obligation to keep it. If you do not plan to pay once the trial ends, it is usually tidier to remove it straight away and rely on the built-in protection, rather than leaving it to expire and nag. If you do intend to buy, compare it with other options first; a trial being pre-installed does not make it the right choice for you.

When the new computer is set up, the NCSC's household guidance on Own Your Online is a good checklist to run through: updates, passwords, two-step verification and backups.

Older and slower computers

Security software uses some of a computer's memory and processing power. On a recent machine this is rarely noticeable. On an older or low-powered computer, a large suite may make everyday tasks feel slower. If you are choosing for an older computer, check the vendor's system requirements carefully, and consider whether the built-in protection, which is designed to fit the operating system, is a lighter option.

It is also worth checking whether the computer still receives operating system updates. If it does not, no security product can fully make up for that, because the gaps that updates would have closed remain open. In that case, planning to replace the computer, or using it only for tasks that do not involve sensitive accounts, may be the more practical step.

When to get help

If a removal fails repeatedly, or the computer behaves oddly afterwards, the vendor's support service is the right first contact for its own product. Be careful how you find that support: search results and advertisements sometimes lead to fake support lines. Go to the vendor's website directly and look for its support or contact page. Lesson six explains why this matters.