Clean Install Windows 11 from USB (2026 Guide)

A clean install of Windows 11 takes about 45 minutes from booting the USB to seeing the desktop. You need an 8 GB USB drive, an ISO from Microsoft, and Rufus to write it. This guide covers Windows 11 25H2 — the current release as of June 2026 — including the Microsoft Account bypass changes that have tripped people up since October 2025.

What You Need Before You Start

Back up first. A clean install deletes everything on the target drive. That's the whole point of it, so don't let it be a surprise.

Requirement	Minimum	Notes
CPU	1 GHz, 2+ cores, 64-bit	Intel 8th Gen+ or AMD Ryzen 2000+ officially supported
RAM	4 GB	8 GB is far more comfortable in practice
Storage	64 GB	SSD strongly preferred; NVMe cuts install time in half
TPM	2.0	Check BIOS if unsure; Rufus can bypass this for unsupported hardware
Firmware	UEFI with Secure Boot	Enable in BIOS before booting the USB
USB Drive	8 GB	16 GB to be safe; everything on it gets wiped

To confirm your TPM status without rebooting, press Win + R, type tpm.msc, and press Enter. "Specification Version: 2.0" means you're fine. "Compatible TPM cannot be found" means it's absent or disabled in BIOS — check the firmware settings before assuming you need a workaround.

Step 1: Download the Windows 11 25H2 ISO

Go to microsoft.com/software-download/windows11. Two routes from that page:

The Media Creation Tool (MCT) downloads and builds the USB directly. Microsoft refreshed it in June 2026, so it now pulls build 26200.8653 with the latest Patch Tuesday fixes already slipstreamed in — you won't spend an hour post-install downloading months of patches. The download is just under 5.5 GB.

The ISO download (scroll to "Download Windows 11 Disk Image") gives you a file you run through Rufus yourself. This is the route to take, because Rufus offers bypass options that MCT doesn't. Pick your language, click Confirm, and download Win11_25H2_English_x64.iso.

Don't use any other source. Third-party ISO sites are unnecessary risk. Microsoft's download page is free and public.

Step 2: Create a Bootable USB with Rufus

Download Rufus 4.14 from rufus.ie. It's portable — no installation, just run the .exe. Skip the 4.15 BETA for anything important.

Settings that matter:

Device — your USB drive. Double-check this. Rufus wipes whatever you select.
Boot selection — click SELECT and point it at your ISO.
Partition scheme — GPT. Use this for any UEFI system, which is anything built in the last decade.
Target system — UEFI (non-CSM).
File system — NTFS. Leave it.

Click START and Rufus shows a "Windows User Experience" dialog. This is the part worth reading:

Remove requirement for 4GB+ RAM, Secure Boot and TPM 2.0 — tick this only if your hardware doesn't meet the official requirements. On a supported machine, leave it unchecked.
Remove requirement for an online Microsoft account — tick this if you want a local account. This is the most reliable way to skip the Microsoft account during OOBE. More on why below.
Disable data collection (Skip privacy questions) — tick it. You can revisit privacy settings after install.

Click OK, confirm the wipe, and let it run. Writing takes 5–15 minutes depending on USB speed. When the status bar shows READY in green, it's done.

Step 3: Boot from the USB

Plug the USB into the target machine and power it on. You need to hit the boot menu before Windows starts loading from the drive. The key varies by manufacturer:

Dell: F12
HP: F9 (or Esc, then F9)
Lenovo: F12 (or the small Novo button near the power port)
ASUS: F8 or Del → Boot Override
MSI: F11
Gigabyte: F12

If you're not sure, tap F12 and Esc repeatedly during the POST screen. One of them usually works. If the USB appears twice — once with "UEFI" in the name and once without — always pick the UEFI entry. Booting the non-UEFI entry installs Windows in legacy MBR mode, and that's a headache to undo.

How to Clean Install Windows 11: The Setup Steps That Actually Matter

Language, keyboard, time zone — click through those. The screen that deserves full attention is "Where do you want to install Windows?"

For a proper clean install, delete every partition on the target drive individually. You'll typically see a System partition (~100 MB), an MSR partition, sometimes a Recovery partition, and the main Windows partition. Select each one and click Delete. Don't touch partitions that belong to any other drive in the list — if you have a data drive, it shows up here too.

Once the partitions are gone, you'll see "Drive 0 Unallocated Space." Select it and click Next. Windows creates its own partition layout — EFI, MSR, Recovery, and the main C: partition. You don't create them manually.

Getting "Windows can't be installed on drive X partition Y"? This usually means the disk is MBR-formatted but you booted the USB in UEFI mode. Deleting all partitions and selecting unallocated space fixes it most of the time. If not, press Shift+F10 to open a command prompt during setup, run diskpart, then list disk, select disk 0, clean, and convert gpt. That command wipes everything on disk 0 — confirm you've selected the right disk before running it.

After selecting unallocated space and clicking Next, setup copies files and reboots a couple of times. On NVMe, the file copy is under 10 minutes. On a SATA SSD, closer to 20. Then you hit OOBE.

How to Skip the Microsoft Account During OOBE

Microsoft removed oobe\bypassnro from the installer image in late 2025 (starting with build 26120.3653), and start ms-cxh:localonly is blocked in current stable builds. Don't waste time on either of those in a 25H2 install.

Option 1 — Rufus (do this before you start): If you checked "Remove requirement for an online Microsoft account" when building the USB, setup skips the MSA screen entirely and drops you into local account creation automatically. This is the clean way to handle it. I've had the other methods fail on fresh installs where MCT created the USB; Rufus doesn't have that problem.

Option 2 — Registry tweak during OOBE: At the account sign-in screen, press Shift+F10 to open a command prompt and run:

reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\OOBE /v BypassNRO /t REG_DWORD /d 1 /f
shutdown /r /t 0

After the reboot, disconnect from the network — unplug Ethernet or click the Wi-Fi icon and disconnect. You'll see "I don't have internet" at the bottom of the connection screen. Click it, then "Continue with limited setup," and you can create a local account.

Option 3 — Windows 11 Pro only: At the account screen, click "Sign-in options" → "Domain join instead." Creates a local account without any command-line work.

After the Install: First Steps

Open Settings → Windows Update and let it run completely before you install anything else. Even a June 2026 MCT build will have a few driver or security updates queued. Check Device Manager (Win+X → Device Manager) for yellow exclamation marks — network adapters and integrated GPUs are the most common missing drivers on a fresh install.

Confirm the version: Settings → System → About → "Windows specifications." You should see Version 25H2 and an OS build starting with 26200.

If Windows isn't activated, go to Settings → System → Activation → "Troubleshoot" → "I changed hardware on this device recently." If the digital license was linked to that hardware from a previous activation, it reactivates after you sign into your Microsoft account through the troubleshooter — even if you set up a local account for daily use.

One last thing worth doing on day one: verify Windows Recovery Environment is intact. Open an elevated command prompt and run:

reagentc /info

You want to see "Windows RE status: Enabled." If it shows Disabled, run reagentc /enable from the same elevated prompt to turn it back on.

Frequently Asked Questions

Do I need a product key to clean install Windows 11?

No — you can skip the key entry during setup. If the digital license is tied to that hardware from a previous activation, Windows activates automatically after connecting to the internet. New hardware that's never been activated needs a valid key.

Can I clean install Windows 11 25H2 over Windows 10?

Yes. The USB install process is identical regardless of what's on the drive. You boot from the USB, wipe the partitions, and install fresh. Windows 10 doesn't need to be running — you're replacing it.

MCT or direct ISO — which should I use?

Download the ISO and run it through Rufus. MCT is faster if your hardware meets every requirement and you're fine with a Microsoft account. Rufus handles edge cases that MCT can't — unsupported hardware, local account setup, skipping the privacy questions. It's the more flexible tool.

My PC fails the TPM 2.0 check. Can I still install?

In Rufus, tick "Remove requirement for 4GB+ RAM, Secure Boot and TPM 2.0." It patches the installer's hardware checks. Many people run Windows 11 on 7th-gen Intel hardware this way. Updates have kept flowing on unsupported hardware so far, but Microsoft doesn't guarantee it, and automatic device encryption won't work without TPM 2.0.

How long does a clean install take?

About 30–45 minutes from booting the USB to the desktop, not counting OOBE and initial update downloads. On a fast NVMe, the file copy completes in under 10 minutes. OOBE itself is another 5–10 minutes if you move through it quickly.

After the clean install, I see a Windows.old folder. Is something wrong?

It appears when setup found an existing installation on the partition you installed onto rather than truly unallocated space. If you deleted all partitions correctly and selected unallocated space, it shouldn't exist. If it does, remove it safely: Settings → System → Storage → Temporary files → "Previous version of Windows" → Remove files.