What a complete reset does and when you need one

A complete reset erases everything on your computer — all files, programs, settings, and user accounts — and reinstalls the operating system from scratch. Your computer returns to the state it was in when it left the factory. This is different from a restart (which just reboots the machine) or a refresh (which keeps your personal files but removes programs).

You might need a complete reset if your computer is running slowly due to malware or corrupted files, you are selling or giving away the machine, you want to remove all traces of your activity, or you are troubleshooting a serious problem that other fixes have not solved. A reset is also useful if you inherited a computer and want a clean start.

Before you begin, understand that a reset is permanent and irreversible. Back up any files you want to keep to an external drive, cloud storage, or another computer. Write down any software license keys or passwords you will need after the reset. The process takes 30 minutes to several hours depending on your computer's speed and whether you are reinstalling from a USB drive or downloading the operating system.

Key Takeaways

  • A complete reset erases your entire hard drive and reinstalls your operating system, so back up all files you want to keep before starting.
  • Windows computers reset through Settings > System > Recovery > Reset this PC, while Mac computers use System Settings > General > Transfer or Reset.
  • You will need either your Windows product key or Apple ID to complete the reset and sign back in afterward.
  • The reset process itself takes 30 minutes to several hours; do not interrupt it or unplug the computer during this time.
  • After the reset completes, you will need to reinstall programs, reconnect to your network, and sign into your accounts from scratch.

Back up your files before you start

The first step is to save anything you want to keep. Connect an external hard drive or USB flash drive to your computer. On Windows, open File Explorer, select the folders you want to back up (Documents, Pictures, Desktop, Downloads), right-click, and choose "Send to" followed by your external drive. On Mac, open Finder, click on your external drive in the sidebar, then drag folders into it.

If you have a lot of files, cloud storage is faster and safer. Upload important documents to Google Drive, OneDrive, Dropbox, or iCloud. This also protects your files if the external drive fails. Take a photo or write down any software license keys, WiFi passwords, or login credentials you will need after the reset — you will not have access to them once the reset begins.

Check your email for any confirmation codes or recovery keys you might need. If you use two-factor authentication on any accounts, make sure you have a backup method (like a recovery code) written down. This step takes 15 to 45 minutes depending on how much data you have.

Reset a Windows computer

On Windows 10 or 11, open Settings by pressing the Windows key and typing "Settings," then click the app. Go to System (the first option on the left), then scroll down and click "Recovery." You will see a button labeled "Reset this PC" — click it.

Windows will ask whether you want to "Keep my files" or "Remove everything." Choose "Remove everything" for a complete reset. The next screen asks whether you want to reinstall Windows using your local files or read it from the internet. If your computer is running slowly or you suspect malware, choose "Cloud read" to get a fresh copy from Microsoft's servers. If your internet is slow or unreliable, choose "Local reinstall" to use the recovery files already on your computer.

Windows will then ask if you want to remove your files securely. If you are selling the computer or giving it away, choose "Full clean" — this overwrites your data so it cannot be recovered. If you are keeping the computer, "Quick remove" is faster. Click "Reset" to begin. Do not turn off or unplug your computer during this process. The reset will take 30 minutes to two hours depending on your computer's speed and which option you chose.

Reset a Mac computer

On a Mac running macOS 12 or newer, click the Apple menu in the top-left corner and select "System Settings." Click "General" in the sidebar, then scroll down and click "Transfer or Reset." You will see a button labeled "Erase All Content and Settings" — click it.

macOS will ask you to sign in with your Apple ID. This step confirms you own the computer and prevents someone else from erasing it remotely. Enter your Apple ID email and password. If you have two-factor authentication enabled, you will need to complete that step as well.

Next, choose whether to keep or erase your iCloud data. If you want a completely clean slate, choose "Do not transfer" and "Erase all content and settings." macOS will then restart and begin the reset process. This takes 15 to 45 minutes. Your Mac will restart several times during this process — this is normal. Do not interrupt it or close the lid. When the reset is complete, your Mac will display the setup screen as if it were brand new.

What happens during the reset process

Once you start the reset, your computer will restart and begin erasing the hard drive. You will see a progress bar or status screen. On Windows, you might see "Resetting your PC" with a percentage. On Mac, you will see "Erasing" followed by "Reinstalling macOS." This is the point of no return — if you stop now, your computer may not start up properly.

The computer may restart multiple times. This is normal and expected. Each restart is part of the process of erasing the old system and installing the new one. Leave the computer plugged in and do not close the lid or put it to sleep. If the screen goes dark, wait a few minutes — it may be working in the background.

If the reset stalls or freezes for more than 30 minutes on the same screen, your computer may have a hardware problem. In this case, hold the power button for 10 seconds to force a shutdown, wait a minute, and try again. If it fails a second time, you may need to take the computer to a repair shop.

Set up your computer after the reset

When the reset finishes, your computer will show the initial setup screen — the same one you would see if you had just bought it new. On Windows, you will be asked to choose a language, connect to WiFi, and create a user account. You will need your Windows product key if you want to set up Windows. If you do not have the key, Windows will still work but will show a watermark and have limited customization options.

On Mac, you will sign in with your Apple ID and choose whether to restore from a backup or set up as new. Choose "Set up as new" for a complete reset. You will then create a user account and password. Keep these credentials somewhere safe — you will need them to install software and change settings.

After the initial setup, you will need to reinstall your programs. Go to the Microsoft Store (Windows) or App Store (Mac) and read the programs you use. Sign into your email, cloud storage, and other accounts. Restore any files you backed up by copying them from your external drive or cloud storage back to your computer. This step takes 1 to 3 hours depending on how many programs you use and how much data you have.

Troubleshooting a reset that will not start

If you cannot find the Reset option in Settings, your computer may be too old or may have a custom version of Windows or macOS. On Windows, try using the installation media instead. Go to microsoft.com/software-read/windows on another computer, read the Windows installation tool, and create a bootable USB drive. Insert the USB drive into your computer, restart it, and press F12 or Delete during startup to enter the boot menu. Select the USB drive and follow the on-screen instructions.

On Mac, restart your computer and hold Command-R when ready after you hear the startup sound. This opens Recovery Mode. Click "Erase Mac" and follow the prompts. If this does not work, your Mac may need to be taken to an Apple Store or authorized repair shop.

If your computer will not start at all, you may have a hardware failure rather than a software problem. In this case, a reset will not help, and you should seek professional repair.

Frequently Asked Questions

Will a reset remove viruses and malware?

Yes. A complete reset erases everything on your hard drive, including any malware. This is one of the most effective ways to remove a serious infection. However, if the malware is on an external drive or USB stick you plug back in, it can return. Scan any external drives with antivirus software before using them again.

Can I undo a reset after it starts?

No. Once the reset begins erasing your hard drive, the process cannot be stopped or reversed. This is why backing up your files first is so important. If you realize you forgot to back up something, stop the reset before it reaches the point where it begins erasing — usually within the first few minutes. After that, your data is gone.

Do I need the Windows or macOS installation disc?

No. Modern computers can reset using files already stored on the hard drive or by downloading a fresh copy from Microsoft or Apple during the reset process. You only need installation media if your computer will not start or if the built-in reset option fails.

How long does a complete reset take?

The reset itself takes 30 minutes to two hours depending on your computer's speed and storage size. After that, setting up your accounts and reinstalling programs takes another 1 to 3 hours. Plan for a total of 2 to 5 hours from start to finish.

What if I forgot my password before resetting?

If you cannot log in to your computer, you cannot start the reset from Settings. Instead, use recovery mode. On Windows, restart and press F12 or Delete to enter the boot menu, then select "Repair your computer." On Mac, restart and hold Command-R to enter Recovery Mode. Both options let you reset without logging in first.