Windows Could Not Prepare the Computer to Boot? 6 Fixies

Was your Windows installation canceled due to a message that Windows could not prepare the computer to boot?

This kind of message could appear when upgrading the current Windows build or reinstalling the existing Windows.

Either way, a couple of problems could be causing this message box to pop up. Some of them could be considered marginal, while others are more complex.

Either way, in this troubleshooting guide, you will learn how to fix this problem and continue with the installation.

What is causing Windows could not prepare the computer to boot error?

As we’ve mentioned, this message could show up as you install a new Windows version or upgrade the current version.

Either way, the message informs you that your Windows was unable to prepare the computer to boot into the next phase of installation and that you should restart the installation.

However, in most cases, this installation error will persist even after you restart your PC, so this may not be the best method to solve this issue.

Before we move on to the most efficient methods of restarting the Windows installation process, we must discuss the core issues causing this Windows installation error.

Your BIOS isn’t supporting this Windows version

It is necessary for the BIOS and the Windows versions you’re attempting to install to be compatible.

If there is a compatibility issue, your Windows operating system will reject this version, and you will be unable to complete the installation process.

Windows installation media isn’t correctly configured

If the Windows installation media isn’t correctly configured, it will affect the installation process and even interrupt it.

Even a corrupted Windows setup file in the installation media could interrupt the existing Windows installation, which is precisely what the message on the screen informs you of.

Unnecessary hardware

There are, in fact, many processes in your Windows OS that could be affected by unnecessary hardware – especially if it is malfunctioning or damaged.

An error or a bug coming from faulty, unnecessary external devices may have compromised the entire Windows installation process.

Outdated BIOS

One of the reasons your BIOS and Windows may not be compatible, even though you made sure that you were using the compatible versions, is that the BIOS is outdated.

An old version of your Windows OS may also create issues with hardware components, which can be the main reason you’re currently unable to update your Windows or install a new one.

UEFI firmware isn’t enabled

An upgrade to Windows 11 calls for a switch from Legacy BIOS mode to UEFI. If you haven’t enabled UEFI firmware before starting the installation process, it may be why it got interrupted.

How to fix Windows could not prepare the computer to boot error

Now that we know what could compromise the Windows installation process, we can move on to solving these issues and ensuring a clean install the next time.

1. Make sure that the BIOS and the Windows versions are compatible

As we’ve mentioned, your motherboard BIOS must be compatible with the Windows version you’re trying to upgrade or install.

The information about BIOS and Windows ISO compatibility is always available on the manufacturer’s website, so you certainly want to check if they’re compatible before launching the Windows installer.

For instance, the Legacy BIOS is not compatible with Windows 11, and even if you succeed in installing it under these conditions, you will be unable to install any new updates.

2. Check the Windows installation media configuration

The best way to rest if a Windows installation media file is corrupted is by creating a bootable USB.

You can recreate the file using either Media Creation Tool or Rufus and create a bootable USB drive with the file.

Plug the USB flash drive into the USB 2.0 port in your computer/laptop, then try to complete the installation process.

3. Remove unnecessary hardware

Anything that isn’t essential to the installation process is considered unnecessary hardware.

That being said, you should remove all the external devices that may jeopardize the installation, including all USB devices, headphones, speakers, and your external hard disk.

Once you’ve unplugged all of these peripherals, please restart your computer and try installing Windows without them.

4. Make sure that BIOS is up to date

An outdated BIOS can create more issues in the computer’s system than we would be able to name in this guide.

As we’ve briefly mentioned, the compatibility issues between the BIOS and the Windows version you’re trying to install may stem from an outdated BIOS.

To ensure you’ve installed all the necessary updates for your BIOS, go to the official manufacturer’s website and navigate to updates. Make sure to follow all the on-screen instructions to install the BIOS update safely.

Keep in mind that, after each update, the BIOS goes back to its default settings, deleting all of your custom settings and adjustments.

After installing the update, you can reconfigure the BIOS according to your custom settings.

5. Enable UEFI firmware on your computer

If you’re installing Windows 11, it is necessary to switch from Legacy BIOS to UEFI to ensure a clean installation and regular updates.

To enable the UEFI firmware on your computer, restart the system, then press the specific button on the keyboard to launch the BIOS settings (this command will be different for every motherboard, and you can find it online or in the user manual).

In the BIOS settings, go to the Boot menu, select Boot Mode, and finally, click on UEFI. To save the changes you just made, press F10 on your keyboard.

6. Disable Secure Boot and CSM

While these options are handy and efficient, they can interfere with installation. Therefore, you should disable them when installing or upgrading your Windows – even if it’s temporary.

The role of the Secure Boot is to boot up the system using only the original equipment manufacturer’s software. At the same time, CMS represents the connection between the UEFI firmware and the Legacy firmware.

To disable the Secure Boot and CSM, restart your computer, then launch the BIOS settings, as we explained in the previous step.

Navigate to the Boot tab, where you should see the CSM Support option. Make sure to disable it.

Next, navigate to Secure Boot and select Disable next to this option in BIOS settings.

Press the F10 key on your keyboard to save these settings and exit the BIOS settings menu. Once the new Windows is installed or the current version is upgraded, you can go back and enable both of these options. 


How do I download Windows 11 setup?

To download Windows 11 setup, launch Settings, then navigate to Update & Security, and select Windows Update.

Now click the Check for updates option. Once the scan is complete, there should be an update to Windows 11 ready for you to download and install on your computer.

To avoid any installation problems and errors, go through the guide above before installing your new Windows and do everything you can to ensure a clean installation.

Does installing Windows 11 delete everything?

The installation of a new Windows version will not delete everything, as long as you choose to “Keep personal files and apps” during the setup of Windows 11. 

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