Official operating system downloads
Every entry below is published by the vendor that makes the software — Microsoft for Windows, Apple for macOS, Canonical and the Fedora and Debian projects for Linux. Each row opens a page on this site that explains what the source is for and links on to the vendor’s own domain; the hostname is printed so you can see where it ends up before you click.
Browse downloads by category
Each category explains which vendor page you need for your situation, then links to a page for every source that opens the vendor’s own domain. This is the fastest way to find the right link.
Windows downloads, by job
Windows 11, Windows 10, the Enterprise evaluation, the Media Creation Tool, and the helper pages for requirements and release status.
macOS downloads explained
Where the installer really comes from — App Store, Software Update and Recovery — plus a USB installer and the developer corner.
USB writing tools
Rufus, Ventoy and balenaEtcher compared: what each writer does, and why the image must still come from the vendor.
Linux downloads
Ubuntu, Fedora and Debian as supported alternatives for hardware that cannot run Windows 11.
Windows
Microsoft publishes the ISO, the media creation tool and the upgrade assistant from one page. Which of the three you want depends on whether you are upgrading in place or building install media.
The only place Windows 11 comes from. The page offers the Installation Assistant for in-place upgrades, the Media Creation Tool for building a USB stick, and the direct ISO download for everything else.
Still available for machines that cannot meet the Windows 11 requirements, or for software that will not run on it. Support ended on 14 October 2025, so treat this as a compatibility fallback rather than a destination.
A full, genuine Windows 11 Enterprise image, free from Microsoft, licensed for 90 days of evaluation. The legitimate option for a test machine, a lab, or a VM you need for a month.
Pre-release Windows builds, from Microsoft, for people who want to test upcoming versions. Opt in and the builds arrive through Windows Update; no ISO hunting required.
Microsoft's own instructions for the Media Creation Tool, including what the tool needs and what it does at each step. Read this instead of a tutorial blog if you want the current wording of every prompt.
Known issues and rollout status for every supported Windows release. Check here before reinstalling: if Microsoft has already acknowledged your symptom, reinstalling will not fix it and will cost you an afternoon.
The actual hardware requirements: TPM 2.0, UEFI Secure Boot, 4 GB RAM, 64 GB storage, a supported CPU. Worth two minutes before you download 5.5 GB.
macOS
Apple does not distribute macOS as a downloadable ISO from a public page. The installers come through the App Store and through its support pages — the links below are those pages, not third-party copies of the result.
Apple's hub for every route to a macOS installer: Software Update, macOS Recovery, Terminal, and the App Store links for the current release and older ones. Start here rather than at a downloads directory.
The createinstallmedia walkthrough, including the exact command for every release back to El Capitan. The command is copied from Apple rather than retyped, which matters: one wrong character produces an unbootable drive.
The canonical answer to “will I lose my files?” Apple states it directly: reinstalling macOS does not remove your apps or personal data. Includes which macOS version you get depending on how you entered Recovery.
How to reach Recovery on both Apple silicon and Intel Macs, and what to do when it will not start. The key combinations differ by chip, and getting this wrong is the most common stumbling block.
Apple's own developer resource centre, which hosts full macOS installers and betas alongside Xcode. Requires a developer account, and carries beta software with the usual caveats.
Where the App Store links on Apple's macOS page lead. The installer downloads as a normal App Store purchase, which is why it appears without a visible ISO.
USB writing tools
These are not operating systems. They are the upstream projects for writing an image to a USB drive, listed because the guides refer to them and because a version downloaded from a bundle site is not the version the project publishes.
The standard tool for writing a Windows ISO to a USB stick. Small, open source, no installer, and it lets you set the partition scheme and target system explicitly — which is what you need when a stick refuses to boot.
Installs a bootloader to a USB drive once, after which you copy ISO files onto it as ordinary files and choose between them at boot. Worth the setup if you reinstall machines regularly or keep several operating systems on one stick.
A cross-platform image writer with the simplest possible interface. Handy when you are preparing a Windows or Linux stick from a Mac, where Rufus is not an option.
Linux
Included for completeness. Most people reinstalling a laptop are choosing between Windows and macOS, but these are the official pages if you are not.
Canonical's own download page for Ubuntu Desktop.
The Fedora Project's official Workstation image.
The Debian Project's official installation images.
Verifying a download
A file arriving from the vendor's own server is your first and strongest protection. If you want to go further, these are the checks that are actually meaningful.
Check the digital signature on Windows media
A genuine Microsoft ISO can be inspected from PowerShell. Mount the image and check its signature:
Get-AuthenticodeSignature D:\setup.exe | Format-List
Look for a status of Valid and a signer of
Microsoft Corporation. A signed setup.exe
means the installation engine is genuine. This does not prove the whole image
is byte-identical to Microsoft's, but a forged signature is not something you
will encounter from a random repack.
Check a macOS installer
Apple installers are signed and notarised. Confirm the app you downloaded is the one Apple shipped:
pkgutil --check-signature "/Applications/Install macOS Sequoia.app"
You want the signature to chain to Apple Inc. Any other result means the installer is not Apple's.
Check disk integrity before you reinstall
Not a download check, but the other reason installs fail. On macOS, run
First Aid from Disk Utility before erasing; on Windows, run
chkdsk on the system drive while the old
installation still works. Finding out the drive is failing after you have
wiped it is a bad trade.
What not to do
Do not download a “verified” image from a file host whose checksum list was published by the same uploader. Do not use a downloader that fetches from several mirrors automatically. And do not install an activation tool of any kind — see the activation section of the Windows guide for what that costs.
What each source is actually for
A table of links tells you where to click. It does not tell you which of Microsoft's three download options fits your job, why a 32 GB stick matters for a macOS installer, or why Rufus is a writer rather than a source. These 18 pages do. Every one of them links back to the vendor's own page.
Microsoft's Windows 11 download page: which of the three options to use
Installation Assistant, Media Creation Tool or a direct ISO — what each one is for, and why the hostname in the address bar is the whole point.
The Windows 10 download page, and its deadline
Why Windows 10 is still downloadable, why it is a compatibility fallback rather than a destination, and how to decide honestly between the two.
The 90-day Windows Enterprise evaluation, used properly
A genuine, free, time-limited image from Microsoft. What it is for, what it is not, and why it is the honest answer to 'I just need a test machine'.
Microsoft's own installation-media instructions
Why the vendor's support article beats a tutorial screenshot when the prompts change, and what the article actually covers.
Apple's macOS Recovery documentation
What Apple's own Recovery articles cover, why the Apple silicon and Intel instructions are separate, and the sentence that protects your files.
Apple's bootable installer instructions
createinstallmedia, the 32 GB stick, and the case where Recovery is not enough. What the command does and what can go wrong.
Rufus: a USB writer, not a source of Windows
What Rufus is for, the options worth leaving alone, and why the image you feed it still has to come from Microsoft.
Ventoy and balenaEtcher: two other ways to write an image
One stick for several installers versus the simplest possible write. When each is useful, and the failure each one introduces.
The Windows Insider Program: pre-release builds, not a free Windows
What the Insider Program actually is, how the builds arrive through Windows Update, and why it is a test channel rather than a source of install media for a production machine.
Windows release health: check this before you reinstall
Microsoft's own dashboard of known issues and rollout status for every supported Windows release, and why reading it can save you from a reinstall that fixes nothing.
Windows 11 system requirements: check before you download 5.5 GB
The published Windows 11 hardware requirements, what each one means in practice, and the honest alternatives when a machine does not qualify.
Where macOS actually comes from: App Store, Software Update and Recovery
Apple does not publish macOS as a public ISO. This page explains the real routes to an installer and why a normal reinstall needs no separately downloaded image.
Apple Developer downloads: full installers and betas, with caveats
Apple's own developer resource centre, which hosts full macOS installers and beta software. What is there, the account it needs, and why betas are not daily-driver material.
The Mac App Store and the macOS installer
Where the App Store links on Apple's macOS page lead, why the installer arrives as a normal purchase, and why there is no visible ISO to save.
balenaEtcher: the fewest-decisions USB writer
What Etcher is for, why its simplicity is about the write and not the source, and how it fits alongside Rufus and Ventoy for writing official images.
Ubuntu Desktop: get the image from Canonical
Canonical's own download page for Ubuntu Desktop, why the image must come from the project's domain, and how it fits a reinstall-or-replace decision.
Fedora Workstation: get the image from the Fedora Project
The Fedora Project's official Workstation image, why it must come from the project's own site, and how it compares as a Linux alternative.
Debian: get the installation images from the Debian Project
The Debian Project's official installation images, why they must come from debian.org, and how Debian fits as a stability-first Linux alternative.