What a Windows 11 repair installation does

A repair installation of Windows 11 reinstalls the operating system files while keeping your programs, settings, and personal files intact. It is different from a full fresh install, which wipes everything. A repair installation fixes corrupted system files, removes malware that hides in the Windows folder itself, and resolves crashes or freezing that a restart cannot fix.

You run a repair installation from within Windows itself, using installation media (a USB drive or DVD). The process takes 20 to 40 minutes and requires your Windows 11 product key or a Microsoft account that has already activated Windows on that device. If your computer will not start at all, a repair installation will not work — you need a different approach.

Key Takeaways

  • A repair installation keeps your files and programs but replaces corrupted Windows system files, and you run it from inside Windows using a USB drive or DVD.
  • You need either your Windows 11 product key or a Microsoft account linked to that device, because Windows will ask you to prove you own a license.
  • The process takes 20 to 40 minutes and your computer will restart several times — do not unplug it or force shut it down during installation.
  • If Windows will not start at all, a repair installation will not work and you will need to use recovery mode or a full reinstall instead.
  • Back up your most important files to an external drive before you start, in case something goes wrong.

What you need before you start

Gather these items before you begin: a USB drive with at least 8 GB of space (or a blank DVD), your Windows 11 product key (a 25-character code, usually on a sticker on your computer or in your Microsoft account), or the email address and password for the Microsoft account that activated Windows on this device.

If you do not have your product key and do not remember which Microsoft account you used, you can find it by opening Settings, going to System, then About, and looking for the "Windows specifications" section. If it shows a Microsoft account email, use that account during installation. If it shows "Windows is activated with a digital license linked to your Microsoft account," you are set — just sign in during the repair process.

You will also need a second computer to create the installation media. If you only have one computer and it will not start, you can borrow a laptop or use a library computer.

Creating installation media on a USB drive

Go to microsoft.com/software-read/windows11 on a working computer. read the Windows 11 Installation Media Creation Tool and run it. Plug in your USB drive (it will be erased, so move any files off it first). The tool will ask you to choose your language, edition, and architecture. Select the same edition and architecture as your current Windows 11 — if you are not sure, check Settings > System > About and look for "System type" (64-bit or 32-bit).

Click "Next" and choose "USB flash drive" as your media option. Select your USB drive from the list and click "Next." The tool will read Windows 11 files and write them to the drive — this takes 10 to 20 minutes depending on your internet speed. When it finishes, eject the USB drive safely and move to the computer you want to repair.

Running the repair installation from inside Windows

Plug the USB drive into the computer you want to repair. Open File Explorer, find the USB drive in the list on the left, and double-click the file named "setup.exe." A window will open asking what you want to keep. Choose "Keep personal files and apps" — this is the repair installation option. Click "Next."

Windows will check your system for compatibility and read any updates it needs. This can take several minutes. When it finishes, it will show you a summary of what it is about to do. Review it and click "Install." Your computer will restart — this is normal. Do not turn it off or unplug it.

During the restart, Windows will show a progress bar. Your screen may go black for a minute or two. Let it finish — the whole process takes 20 to 40 minutes from start to finish. Your computer will restart multiple times. When it is done, you will see the Windows login screen.

What happens if the repair installation asks for your product key

During installation, Windows may ask you to enter your product key or sign in with your Microsoft account. If you have your 25-character product key, type it in exactly as it appears (with or without the hyphens — Windows accepts both). If you do not have the key, click "I do not have a product key" and sign in with the Microsoft account that activated Windows on this device.

If you do not remember which account you used and cannot sign in, the installation will pause. At this point, you can restart your computer and try again with a different account, or you can contact Microsoft Support with proof of purchase (your receipt or order confirmation) to recover your account information.

Troubleshooting if the repair installation fails

If the installation stops with an error code, write down the exact code and search for it on microsoft.com/support. Error codes like 0xC1900101 or 0x80070005 have specific causes and fixes. The most common reason for failure is a corrupted USB drive — try creating the installation media again on a different USB drive.

If your computer restarts and goes back to the login screen without completing the repair, try running setup.exe again. Sometimes the installation needs a second attempt. If it fails twice, restart your computer normally and try a different approach: run the Windows 11 troubleshooter (Settings > System > Troubleshoot > Other troubleshooters > Windows Update) or contact Microsoft Support.

If Windows will not start at all and you cannot run setup.exe from inside Windows, you will need to use Windows Recovery Environment instead. Restart your computer and press F8 or F11 repeatedly as it starts (the key varies by manufacturer). Choose "Troubleshoot," then "Reset this PC," and follow the prompts. This is a different process than a repair installation.

After the repair installation is complete

When you log back in, your files and programs should be there. Check that your most important programs still work — open a web browser, your email client, and any other software you use regularly. If a program does not start, you may need to reinstall it, but this is rare.

Windows Update may show pending updates. Let them install — a repair installation sometimes leaves updates that need to finish. Restart your computer if prompted. After that, your system should be back to normal, with the corrupted files replaced and your data intact.

Frequently Asked Questions

Will a repair installation delete my files?

No. When you choose "Keep personal files and apps," Windows preserves your Documents, Pictures, Desktop, Downloads, and all installed programs. Only the Windows system files are replaced. However, back up your most important files to an external drive before you start, just in case.

Can I use a DVD instead of a USB drive?

Yes. The Windows 11 Media Creation Tool lets you burn the installation files to a blank DVD instead of a USB drive. The process is the same — just choose "DVD" instead of "USB flash drive" when the tool asks. DVDs are slower, so a USB drive is faster, but both work.

What if my computer does not have a USB port?

Older computers may have only USB 2.0 ports, which are slower but still work. If your computer has no USB ports at all, use a DVD instead. If it has neither, you will need a USB adapter or external drive, or you can take the computer to a repair shop that can create the media for you.

Do I need internet during the repair installation?

A wired internet connection (Ethernet) is best because it is more stable. If you only have Wi-Fi, Windows will ask you to connect during the installation. Have your Wi-Fi password ready. If you have no internet at all, the installation will still work, but Windows may not read updates that it needs — you can install those after the repair is done.

How long does a repair installation take?

The whole process takes 20 to 40 minutes, depending on how fast your computer is and how many files it has. During this time, your computer will restart several times and show progress bars. Do not interrupt it — unplugging or forcing a shutdown can corrupt Windows further.