Upgrade Linux Dual-Boot to Windows 10

Upgrading to Windows 10 from a Linux Dual-Boot System

For those utilizing a Linux operating system, it’s common to have it installed in conjunction with an older version of Windows, such as 7 or 8.1, in a dual-boot setup.

It is possible to obtain the complimentary Windows 10 upgrade without compromising the functionality of your currently installed Linux system.

Recovering Windows 10 Eligibility After Linux Installation

Even in scenarios where the initial Windows installation has been replaced by Linux, acquiring the free Windows 10 upgrade remains achievable.

However, this requires a preliminary step: the reinstallation of the original Windows version prior to proceeding with the upgrade.

Successfully reinstating your previous Windows installation will then allow you to take advantage of the free upgrade offer to Windows 10.

Essential Prerequisites

Windows 10 is nearly available, and understanding the requirements for a smooth transition is crucial.

The process of upgrading a system configured for dual-booting mirrors that of a standard Windows upgrade. A valid, activated license for either Windows 7, inclusive of Service Pack 1, or Windows 8.1 is necessary. Users with older versions of Windows 7 or Windows 8 can obtain a free upgrade to meet these prerequisites.

Restoring Windows for Upgrade

Should Linux have been installed over the initial Windows installation, reinstating the original Windows version that accompanied your computer is a mandatory step before initiating the upgrade to Windows 10.

However, if Linux is set up in a dual-boot arrangement and the original Windows system remains intact, the upgrade process can proceed without issue.

Data Backup Recommendation

Prior to commencing the upgrade, creating backups of all important data is strongly advised. While this method has proven successful and is not anticipated to cause complications, official support from Microsoft is not guaranteed.

Upgrading Windows on a Dual-Boot System

Related: A Guide to Upgrading from Windows 7 or 8 to Windows 10

The upgrade process begins by restarting your computer and selecting the Windows option within the boot loader. Within Windows, obtain the media creation tool from Microsoft’s website. Launch this tool and choose the option to "Upgrade this PC."

This procedure mirrors the standard upgrade process used for Windows 7 or 8.1 systems. Alternatively, the Windows 10 ISO can be downloaded from a Linux environment and then burned to a disc.

Following this, reboot into Windows 7 or 8.1 and initiate the setup program from the disc. It is crucial to run the installer from within the Windows 10 environment and specifically select the upgrade option.

A clean installation of Windows 10 isn't possible until the upgrade process is completed first. This initial upgrade effectively activates the free Windows 10 license for your PC. Microsoft’s activation servers will register your PC’s hardware configuration as authorized to use Windows 10.

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Proceed through the standard Windows upgrade process as if it were the sole operating system on the machine. Upon reboot, you will return to the GRUB2 boot loader menu.

Each time the computer restarts, consistently select the “Windows” option from this menu. While the exact naming may vary slightly depending on the Linux distribution, the term "Windows" will always be present in the menu entry.

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Windows 10 will install without issue, replacing the existing Windows 7 or 8.1 installation. The functionality will be identical to that of a PC with only Windows 7 or 8.1 initially installed.

Because this is an upgrade, you will not be prompted to configure partitioning or similar settings. Windows 10 will simply overwrite the existing Windows 7 or 8.1 system on the current partitions, leaving your Linux partitions untouched.

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Important Note: Your Linux installation will remain fully functional after the Windows 10 upgrade.

The GRUB2 Boot Loader and Windows Compatibility

GRUB2 is often affected when installing or updating Windows. A common issue is that the Windows installation process can overwrite the Linux boot loader.

This can render your Linux system inaccessible, requiring either a Linux reinstallation or a GRUB2 repair. Upon startup, the system will default directly to Windows.

Therefore, it’s generally recommended to install Windows prior to Linux when configuring a dual-boot environment.

Unexpected Behavior with Windows 10 Upgrades

Interestingly, the Windows 10 upgrade process demonstrates different behavior. It typically does not overwrite the existing GRUB2 boot loader on Linux systems.

Following the upgrade, the system should function as expected, presenting the familiar Linux boot loader upon each reboot.

Selecting the "Windows" option within the boot loader will then initiate the upgraded Windows 10 operating system, rather than the previous Windows version.

Key Considerations

Installing Windows after Linux is generally advised for dual-boot setups.
Windows 10 upgrades often coexist peacefully with GRUB2.
A GRUB2 repair may be necessary if a standard Windows installation overwrites the boot loader.

This compatibility allows for a smoother transition to Windows 10 without disrupting the existing Linux installation.

Updating Your GRUB2 Boot Menu After a Windows Upgrade

While functionality remains unaffected, your Linux distribution may not automatically update the operating system label within the GRUB bootloader. The entry might still display "Windows 7" or "Windows 8," despite launching Windows 10.

This discrepancy is purely cosmetic and doesn't impede system operation. You can choose to disregard it entirely. However, if you prefer to reflect the correct operating system name, you'll need to manually edit your GRUB2 boot menu.

For Ubuntu users, the Grub-Customizer tool, available through a specific PPA, provides a user-friendly graphical interface for renaming boot entries. Alternative Linux distributions may offer integrated tools for boot menu modification.

Using Grub-Customizer

This tool also allows you to designate Windows 10 as the default operating system, initiating it automatically upon each system startup, if desired. This can streamline the boot process for frequent Windows users.

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The upgrade process is designed to be non-invasive, preserving your existing Linux bootloader. This represents a significant improvement over previous Windows versions.

However, for future installations, it's still recommended to install Windows 10 before Linux. A clean installation of Windows 10 will overwrite the Linux bootloader with the Windows bootloader.

Reinstalling Windows 10

Following a successful upgrade, you can perform a clean install of Windows 10 on the same computer. Microsoft retains a record of the hardware's eligibility for the free Windows 10 offer and its licensing status.

During the installation process, simply bypass the product key prompt at each request. Windows 10 will automatically activate online upon reaching the desktop, verifying its license with Microsoft servers.