How to Upgrade to Windows 8.1

Download the Windows 8.1 installer from Microsoft, and then follow the on-screen prompts to complete the update

Windows 8.1 is an update to Windows 8, much in the same way that service packs were updates to previous versions of Windows, like ​Windows 7. This major update is completely free to all Windows 8 owners.

Let's start this tutorial with a few preparatory steps that you may not see Microsoft or other websites recommend.

It's recommended that you update to Windows 11 because Windows 8.1 stopped receiving security updates in January 2023. Learn how to upgrade to Windows 11 from Windows 8 if you need help.

Before You Start

The following is an ordered list of tasks you should consider completing prior to starting the update process. These suggestions are based on years of experience troubleshooting and solving various problems seen during software installations, Windows updates, and service pack installs—all very similar to this Windows 8.1 update.

  1. Make sure that at least 20% of the space on your primary drive is free. The Windows 8.1 upgrade process will check to see that you have the minimum space necessary for it to do its business, but here's your chance to make sure there's plenty of wiggle room before being warned about it.
  2. Write down your product key. You'll need it during Windows setup. If you're not sure what it is, there are software programs that can help you find it, or look on the DVD or in the email that you received when you first purchased Windows 8.
  3. Apply all Windows updates and then restart your PC after they're done installing, even if you're not prompted to. If you've never checked for updates manually before, you can do it from the Windows Update applet in Control Panel. Issues with Windows Update are relatively common. You don't want to find yourself dealing with a problem caused by a tiny security update pushed two months ago during a major operating system update like Windows 8.1.
  4. Restart your computer. The easiest way is from the power icon, accessible from Settings on the charms menu (swipe from the right and then Settings, or WIN + i). Most computers are rarely truly restarted; they often sleep and hibernate, but are seldom shut down and started up from scratch. Doing so prior to updating ensures that Windows, as well as your computer's hardware, is starting clean.
  5. Disable the real-time protection in Windows Defender. You can do this from the Settings tab in Windows Defender, which you can access from the Windows Defender applet in Control Panel. It also would be wise to run a Full scan using Windows Defender prior to updating Windows. Similar to the Windows updates discussion above, you probably don't want to see the first signs of a virus or other malware just as Windows 8.1 is trying to finish installing.

This tutorial will walk you through the entire process of updating your copy of Windows 8 to Windows 8.1, which takes about 30 to 45 minutes. If you have a previous version of Windows (like 7, Vista, etc.) and want to upgrade to Windows 8.1, you'll need to purchase a copy of Windows 8.1 (Windows 8 with the 8.1 update already included).

Once you've done all the prep work, it's time to move on to Step 1 to start the Windows 8.1 upgrade.

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Download the Windows 8.1 Installer

Select edition and product language menus on Windows 8.1 download page

Visit the Windows 8.1 download page and choose your Windows version from the drop-down menu, followed by Confirm. On the same page, select your language and then choose Confirm again.

Finally, select the version you want to run, either 64-bit Download or 32-bit Download.

The ISO file will start downloading to your computer or you'll be prompted to choose where to save it. Pick a location that's easily accessible later, and feel free to keep the file name as it is by default.

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Mount the ISO as a Virtual Disc

Mount a disc image option for Windows 8.1

Instead of putting the software on a disc and booting to it, we'll simply mount it as a virtual disc.

Windows 8 has a built-in method for mounting ISOs, but there are also third-party programs like WinCDEmu that will work.

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Start the Windows 8.1 Installer

setup file right-click menu from Windows 8.1 disc

Open the virtual disc to start the Windows 8.1 Setup utility. One way to do that is by opening the "disc" and then executing setup.

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Download and Install Updates

Get important updates screen in Windows 8.1 setup

The first screen has you install important updates. Continue by selecting Download and install updates (recommended).

Select Next.

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Enter Your Product Key

Product key text box in Windows 8.1 setup

Setup will refresh briefly (you'll miss it if you look away for even a few seconds) and then you'll be told to enter the Windows 8 product key.

Enter the key you recovered earlier and then press Next.

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Accept the License Terms

License terms in Windows 8.1 setup

Read through the license terms, check the box at the bottom left, and then select Accept.

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Choose What to Keep

Keep personal files only button in Windows 8.1 setup

On this screen, select Keep personal files only if you want the update to not delete your personal files. Or, to erase everything and start fresh, choose Nothing.

Select Next.

You'll see another page, called What needs your attention, if something isn't compatible with the update or if Windows needs you to know that something will change from the way Windows currently is. If so, review it and then select OK.

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Start the Install

Ready to install review page in Windows 8.1 setup

On the Ready to install page, choose Install.

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Wait While Windows 8.1 Installs

Installing Windows 8.1 progress page

There's nothing to do for this step except wait. Windows 8.1 will install, and during this time, the computer might restart, even multiple times. Just be patient as it finishes everything it needs to.

If you see a black screen with white text that says to press any key to boot to the disc (if one is inserted), do not press any key. This will interrupt the installation.

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Finish Setting Up Windows 8.1

Windows 8.1 personalize screen

After the final reboot, Windows 8.1 will be installed, and you'll be told to personalize setup. Walk through the various screens and complete them as you see fit.

The steps include choosing a region and language setting, entering a name for the computer, customizing settings, setting up user accounts, and opting in to online services.

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