What a complete restart does and when you need one

A complete restart — also called a factory reset or clean install — erases everything on your computer and reinstalls the operating system from scratch. This is different from a regular restart, which just closes your programs and reboots. A complete restart removes all your files, programs, and settings, then returns the machine to the state it came in.

You might do this if malware has infected your system so deeply that antivirus software cannot clean it, if you are selling or giving away the computer and want to may support no personal data remains, or if your system has become so cluttered or corrupted that it no longer runs reliably. It is also the most thorough way to remove traces of your activity before handing a device to someone else.

Before you start, understand that this process is permanent and irreversible. Everything stored on the drive — documents, photos, email, browser history, saved passwords — will be gone. Back up anything you want to keep first.

Key Takeaways

  • A complete restart erases your entire drive and reinstalls the operating system, so back up any files you want to keep before you begin.
  • On Windows, use Settings > System > Recovery > Reset this PC; on Mac, restart in Recovery Mode and use Erase and Reinstall from the Utilities menu.
  • You will need your Windows product key or Apple ID to complete the process, depending on your operating system.
  • After the restart finishes, your computer will restart several times and ask you to set up as if it were brand new.
  • A complete restart removes malware more thoroughly than antivirus software alone, but it also removes all your personal data permanently.

How to restart Windows completely

On Windows 10 or 11, go to Settings (the gear icon), then select System from the left menu. Scroll down and click Recovery. Under "Reset this PC," click the blue Reset PC button.

Windows will ask whether you want to keep your files or remove everything. Choose Remove everything to do a complete restart. The system will then ask whether you want to remove files and clean the drive. If you are concerned about data recovery, select Remove files and clean the drive — this takes longer but makes it much harder for someone to recover deleted data later.

Windows will ask for your product key or to sign in with your Microsoft account. Have this information ready. The process will then begin, and your computer will restart multiple times. Do not turn it off or unplug it during this time. The whole process typically takes 30 minutes to two hours depending on your drive size and the option you chose.

When it finishes, your computer will boot into the Windows setup screen as if it were brand new. You will need to choose your language, create or sign into a user account, and configure basic settings before you can use it again.

How to restart a Mac completely

On a Mac, restart your computer and when ready hold down Command + R as it boots up. Keep holding until you see the Apple logo or a spinning globe. This boots you into Recovery Mode, a special environment separate from your main operating system.

Once in Recovery Mode, open the Utilities menu at the top and select Erase and Reinstall (on newer Macs) or Reinstall macOS (on older ones). If you see Disk Utility instead, click that, select your main drive from the list on the left, click Erase, and confirm. Then go back and select Reinstall macOS.

You will need your Apple ID and password to complete the reinstall. macOS will read and reinstall the operating system, which can take 30 minutes to several hours depending on your internet speed and drive size. Your Mac will restart several times during this process.

When it finishes, your Mac will boot into the setup screen. You will need to sign in with your Apple ID and configure your preferences before the computer is ready to use.

What to back up before you restart

Before you begin, connect an external drive and copy anything you want to keep. This includes documents, photos, videos, music, and any files in your Downloads or Desktop folders. Most people forget about email — if you use a desktop email program like Outlook or Mail, export your messages and contacts first. Cloud-based email like Gmail is automatically backed up online, so you do not need to do anything.

If you have programs you paid for or installed from sources other than the official app store, note down their names and where you got them. You will need to reinstall them after the restart. For programs from the Microsoft Store or Mac App Store, your account will remember your purchases, so you can reinstall them for free.

Write down any passwords you have saved in your browser, since those will be erased. If you use a password manager like Bitwarden or 1Password, make sure you have your master password written down somewhere safe. The password manager's vault is usually stored in the cloud, so you can sign back in after the restart.

What happens to your data after a complete restart

When you choose to remove everything, the operating system marks your files as deleted but does not always physically overwrite them when ready. This means someone with specialized software could potentially recover deleted files from your drive — especially if you only did a standard deletion without the "clean the drive" option.

If you are selling or donating the computer and want to make data recovery as difficult as possible, choose the option to clean the drive (Windows) or use Disk Utility's find erase feature (Mac). These options take longer but overwrite the deleted data with random information, making recovery much harder.

If you are restarting because of malware, a complete restart is more thorough than running antivirus software. Malware that has embedded itself deeply in the system cannot hide from a complete reinstall of the operating system itself. However, if the malware is on an external drive or in cloud storage, it will still be there after you restart — only the computer itself is cleaned.

Troubleshooting a restart that gets stuck

If your restart process stops responding or gets stuck on a loading screen, wait at least 30 minutes before doing anything. These processes are slow and can appear frozen when they are actually working. If it has genuinely not moved in an hour, you can force shut down by holding the power button for 10 seconds, then try again.

If you cannot get into Recovery Mode on a Mac, try restarting and holding Command + Option + R instead, which boots into Internet Recovery and downloads the operating system from Apple's servers. This is slower but works if your local Recovery partition is damaged.

On Windows, if the reset keeps failing, try booting from a Windows installation USB drive instead. You can create one on another computer using the Windows Media Creation Tool (available free from Microsoft's website). Insert the USB drive, restart your computer, and press F12 or Delete during startup to choose the USB as your boot device. Then select "Repair your computer" and choose the reset option from there.

After your restart is complete

Once your computer finishes restarting and you have gone through the initial setup, take time to configure your security settings before you restore your files. Turn on Windows Defender (Windows) or enable FileVault (Mac). Set up a strong password for your user account — at least 12 characters with uppercase, lowercase, numbers, and symbols.

Before you restore your backed-up files, scan them with antivirus software if you restarted because of malware. This is especially important for executable files (.exe on Windows, .app on Mac) and files from email or downloads. Restore your files in batches and monitor your system for signs of problems.

Reinstall your programs one at a time from trusted sources. If you originally got a program from a third-party website rather than the official app store, consider whether you still need it or whether there is a safer alternative. This is a good time to remove programs you no longer use.

Frequently Asked Questions

Will a complete restart remove viruses and malware?

A complete restart removes malware from the operating system itself, which is more thorough than antivirus software alone. However, if the malware is stored on an external drive, USB stick, or in cloud storage, it will still be there. After restarting, scan any backed-up files before you restore them, and be cautious about what you reinstall.

Can I restart just part of my computer instead of everything?

Yes. If you only want to remove a specific program or user account, you can uninstall the program or delete the account without restarting the whole system. If you want to remove malware but keep your files, run a full antivirus scan in Safe Mode first. A complete restart is the most thorough option, but it is not always necessary.

What if I forget my password before I restart?

On Windows, you can reset your password during the setup process after the restart finishes — it will ask you to create a new one. On Mac, you will need your Apple ID to set up the computer after the restart. If you do not have access to either, you may need to contact Apple or Microsoft support with proof of ownership.

How long does a complete restart actually take?

A typical complete restart takes 30 minutes to two hours on a modern computer with a solid-state drive. Older computers with traditional hard drives can take three to four hours. The process includes downloading and installing the operating system, so it depends partly on your internet speed. Do not interrupt it or turn off your computer during this time.

Do I need to buy Windows or macOS again after a restart?

No. Windows and macOS are tied to your device or account. After a restart, Windows will recognize your product key or Microsoft account, and macOS will recognize your Apple ID. You do not need to purchase them again. Paid programs from the Microsoft Store or Mac App Store can be reinstalled free on the same account.