What is a factory reset — and should you do one?

What exactly happens during a factory reset?

When you factory reset a device, the operating system removes everything added after it was first set up — your documents, photos, installed applications, saved passwords, browser history, personalised settings and user accounts. What remains is the base operating system in its original configuration, exactly as it was when the device first powered on.

On modern Windows PCs and laptops, the reset process reinstalls Windows from a recovery partition built into the drive. On a Mac, it restores macOS using a recovery tool baked into the chip. On both platforms you can choose between a quick reset (fast, but old data may be recoverable with specialist software) and a secure wipe (slower, overwrites the drive so data cannot be retrieved).

The key point: a factory reset is a one-way door. Once it completes, there is no undo. Back up anything you need before you start.

What does a factory reset delete — and what stays?

Understanding exactly what goes and what remains avoids nasty surprises.

What gets deleted:

• All your personal files — documents, photos, videos, downloads
• Installed applications and games
• Browser history, bookmarks and saved passwords (if stored locally)
• User accounts and their associated settings
• Wi-Fi passwords and network configurations
• Desktop wallpaper, display preferences, accessibility settings
• Any malware, spyware or unwanted software — more on this below

What stays:

• The operating system itself (Windows, macOS, Chrome OS)
• Firmware — the low-level software that runs the hardware
• Files stored in cloud services like OneDrive, Google Drive or iCloud remain in the cloud and re-sync when you log back in
• On some devices, pre-installed manufacturer apps may be restored

Five good reasons to factory reset your device

A factory reset is not something you do lightly, but in these situations it’s often the best option:

1. Selling or giving away the device. This is the most important use case. A factory reset with secure wipe ensures the new owner cannot access your personal files, saved passwords or browsing history. Never skip this step.
2. Persistent malware or ransomware. Some infections are stubborn enough that even good antivirus software cannot fully remove them. A factory reset, combined with a fresh OS install, is the nuclear option — and sometimes the only reliable one.
3. Severe performance degradation. A device that has slowed to a crawl after years of use — bloatware, fragmented storage, redundant processes — often responds dramatically to a clean reset. It won’t fix failing hardware, but it can make an old machine feel like new again.
4. Software that cannot be uninstalled. Occasionally an application, driver or system component becomes corrupted in a way that prevents normal removal. A reset cuts through all of it.
5. Starting completely fresh. If you’ve had the same setup for years and it’s become a sprawling mess of old apps, duplicate files and forgotten configurations, a reset is the cleanest possible fresh start.

“A factory reset is the nuclear option — but sometimes it’s the right one.”

Does a factory reset remove viruses and malware?

In the vast majority of cases, yes. Because a factory reset wipes and reinstalls the operating system, any malware living in user-space — which is almost all of it — is eliminated along with everything else.

There is a narrow exception: firmware-level malware (sometimes called a rootkit or BIOS malware) that has embedded itself below the operating system. This type of infection is rare and typically associated with sophisticated, targeted attacks rather than everyday consumer threats. If you’ve been hit by a standard virus, ransomware or spyware, a factory reset will almost certainly clear it.

How to factory reset: Windows, Mac and Chrome OS at a glance

The exact steps differ slightly by operating system, but the principle is the same on all of them: go into settings, find the reset option, choose your wipe level, and confirm. Here’s the quick path on each platform.

Should you factory reset before selling or trading in your device?

Yes — always, without exception. A factory reset is the minimum you should do. For extra peace of mind, use the secure overwrite option available on Windows and macOS, which overwrites the drive with random data so that your personal files cannot be recovered even with specialist tools.

This matters because simply deleting files or even doing a basic reset without the secure wipe option leaves data in a technically recoverable state. Most buyers won’t attempt to recover it, but the risk is not worth taking.

Before you reset, also make sure you have:

• Signed out of all accounts — Apple ID, Microsoft account, Google account
• Deactivated any software licences tied to the device (Adobe, Office, etc.)
• Removed any SIM cards or memory cards
• Saved or transferred your backups to a separate location

One thing to always do before you reset

Back up. Everything. Before you touch the reset option.

It sounds obvious, but it’s easily forgotten in the moment — especially when you’re rushing to prepare a device for sale or reacting to a malware infection. Use an external hard drive, a USB drive, or a cloud service. Check that your most important folders — Documents, Desktop, Downloads, Pictures — are included. Then check again.

A proper backup takes 20 minutes. Regretting the loss of five years of photos takes considerably longer.

Frequently asked questions