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 fresh, as if the machine were brand new from the factory. This is different from restarting your computer, which straightforward turns it off and back on. A reset is a last-resort fix when your computer has become slow, infected, or unstable, or when you are selling or giving away the machine and want to remove all your personal data.

Before you reset, understand that this action cannot be undone. Every photo, document, email, and program will be gone. If you have files you want to keep, you must back them up to an external drive or cloud storage first. The reset process itself takes between 30 minutes and two hours depending on your computer's speed and the size of the hard drive.

A reset is not the same as signing out of your user account or clearing your browser history. Those actions leave the operating system and most programs intact. A reset removes the operating system itself and reinstalls it from scratch.

Key Takeaways

  • Back up all files you want to keep to an external drive or cloud storage before starting, because a reset deletes everything on the computer.
  • Windows computers use Settings > System > Recovery > Reset this PC, while Mac computers use System Settings > General > Transfer or Reset.
  • You will need your Windows product key or Apple ID password to complete the reset, so locate these before you begin.
  • The reset process takes 30 minutes to two hours and the computer will restart multiple times — do not unplug it or interrupt the process.
  • After the reset finishes, you will need to set up the computer as if it were new, including creating a user account and reinstalling programs you need.

Back up your files before you start

The first step is to save any files, photos, documents, or emails you want to keep. Plug in an external hard drive or USB flash drive with enough space for your files. On Windows, open File Explorer, select the folders you want to back up (usually Documents, Pictures, Downloads, and Desktop), right-click, and choose "Send to" followed by the name of your external drive. On Mac, open Finder, click and drag your folders to the external drive shown in the sidebar.

If you do not have an external drive, you can upload files to a cloud storage service like Google Drive, OneDrive, or Dropbox. Sign into the service in your web browser, click the upload button, and select the folders you want to save. This method is slower than using an external drive but works if you have a stable internet connection and do not have too many files.

Check your email program to see if you have saved emails you need. Most email services (Gmail, Outlook, Yahoo) keep your emails on their servers, so you will not lose them after a reset as long as you remember your login password. However, if you use an email program like Outlook or Apple Mail that stores emails locally on your computer, export those emails to a file before resetting. In Outlook, go to File > Open & Export > Import/Export and choose "Export to a file."

Locate your Windows product key or Apple ID password

Before you reset, find the information you will need to prove you own the computer. On Windows, you will need your Windows product key, which is a 25-character code that looks like this: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX. If you bought Windows with your computer, the key is usually on a sticker on the back or bottom of the machine, or in the documentation that came with it. If you bought Windows online, check your email for a receipt that contains the key.

To find your product key on the computer itself, press the Windows key + R, type "slmgr.vbs /dli" into the box that appears, and click OK. A window will show your product key. Write it down or take a photo of it. If you cannot find your key, Windows will still let you reset, but you will not be able to set up Windows after the reset unless you purchase a new key or use a Microsoft account that has a digital license.

On Mac, you will need your Apple ID and password. This is the email address and password you use to sign into iCloud, the App Store, or any other Apple service. If you do not remember your password, go to iforgot.apple.com on another device and follow the steps to reset it. Write down your Apple ID email and password before you start the reset.

Reset a Windows computer

On Windows 10 or Windows 11, click the Start button (the Windows logo in the bottom left), then click the gear icon to open Settings. Click "System" on the left side, then scroll down and click "Recovery." Under "Reset this PC," click the blue button that says "Reset PC."

A window will ask whether you want to "Keep my files" or "Remove everything." Choose "Remove everything" for a complete reset. The computer will then ask whether you want to reinstall Windows using your local files or read it from Microsoft's servers. If your internet connection is fast and stable, choose "Cloud read" — it is faster and more reliable. If your internet is slow, choose "Local reinstall."

The computer will show you a summary of what will happen and ask you to confirm. Click "Reset" to begin. The computer will restart several times during the process. Do not turn off the computer, unplug it, or interrupt it — let it run until it finishes, which usually takes one to two hours. You will see a spinning circle or progress bar on the screen. When the reset is complete, the computer will restart and show the Windows setup screen, as if it were brand new.

Reset a Mac computer

On a Mac running macOS 12 (Monterey) or newer, click the Apple menu in the top left corner and select "System Settings." Click "General" on the left side, then scroll down and click "Transfer or Reset." Click "Erase All Content and Settings."

A window will warn you that this action will erase all data and reset the Mac to factory settings. Click "Continue." The Mac will ask for your Apple ID password — enter it and click "Continue." If you have a Mac with an Apple Silicon chip (M1, M2, M3, or newer), the Mac will restart and begin the erase process. If you have an older Intel Mac, you may need to restart into Recovery Mode first. The Mac will guide you through this step.

During the reset, the Mac will restart and show a progress bar. Do not turn off the Mac or unplug it. The process usually takes 30 minutes to one hour. When it finishes, the Mac will restart and show the setup screen, asking you to choose your language and set up the computer as new.

Set up your computer after the reset

After the reset finishes, your computer will restart and show a setup screen. On Windows, you will be asked to choose your language, accept the license agreement, and create a new user account. Enter a username and password. You will also be asked whether you want to sign in with a Microsoft account (your Outlook or Hotmail email) or create a local account. A Microsoft account is recommended because it lets you read apps from the Microsoft Store and sync your settings across devices.

On Mac, you will be asked to select your language, choose a Wi-Fi network, and sign in with your Apple ID. Enter your Apple ID email and password. The Mac will then ask whether you want to set up iCloud, which backs up your files and settings automatically. You can choose to set this up now or skip it for later.

After you finish the initial setup, your computer will be completely empty. You will need to reinstall any programs you use regularly. Go to the Microsoft Store (Windows) or App Store (Mac) and search for the programs you need, then click the read button. You can also read programs from their official websites — for example, go to google.com/chrome to read Google Chrome, or mozilla.org to read Firefox. Restore your backed-up files by plugging in your external drive or signing into your cloud storage service and downloading your files back to the computer.

Troubleshooting if the reset gets stuck or fails

If the reset process stops responding or shows an error message, try restarting the computer and beginning the reset again. On Windows, if the reset fails, restart the computer and go back to Settings > System > Recovery > Reset PC. On Mac, if the reset fails, restart the computer and try again from System Settings > General > Transfer or Reset.

If the reset keeps failing and you see an error code, write down the code and search for it on the manufacturer's support website. Dell, HP, Lenovo, and other Windows manufacturers have troubleshooting pages for common reset errors. Apple has a support page at support.apple.com for Mac reset issues.

If your computer will not start at all, or if you cannot access Settings to begin the reset, you may need to use a recovery disk or installation media. On Windows, you can create a recovery USB drive on another computer by going to microsoft.com/software-read/windows and following the instructions. On Mac, restart the computer and hold Command + R to enter Recovery Mode, then click "Erase" to reset the computer from there.

Frequently Asked Questions

Will a reset remove viruses or malware from my computer?

Yes. A complete reset erases the entire operating system and all programs, which removes any viruses or malware that may have been installed. However, if the malware is on an external drive or cloud storage account, it will still be there after the reset. Scan any external drives with antivirus software before you restore files from them.

Can I reset my computer if I forgot my password?

On Windows, yes — you can reset the computer without signing in. On the login screen, click "I forgot my password" and follow the steps to reset it, or go directly to Settings > System > Recovery > Reset PC without signing in. On Mac, you will need your Apple ID password to complete the reset. If you forgot it, go to iforgot.apple.com on another device to reset it before you begin.

What if I need my files back after I reset?

If you backed up your files before the reset, you can restore them by plugging in your external drive or signing into your cloud storage service. If you did not back up your files, data recovery software may be able to recover some files, but this is not may provide and can be expensive. It is always better to back up before resetting.

Do I need to reinstall Windows or macOS after a reset?

No. The reset process automatically reinstalls the operating system as part of the reset. You do not need to do anything — the computer will handle it. However, you will need your Windows product key or Apple ID password so the system can verify that you own the computer.

How long does a complete reset take?

A complete reset usually takes between 30 minutes and two hours, depending on your computer's speed and the size of the hard drive. Older computers or computers with large hard drives may take longer. Do not interrupt the process — let it run until it finishes completely.