Omarchy Dual Boot With Windows: What to Know Before Installing

Omarchy can dual boot beside Windows, but the safe order is:

prepare Windows first, create unallocated space second, install Omarchy into that free space third, then verify both systems boot.

Do not begin by deleting partitions from the Linux installer.

Back up Windows before touching partitions

A correct shrink operation normally preserves Windows.

That does not make partitioning risk-free.

Before starting:

• back up important files;
• know your Windows login credentials;
• save any needed Windows recovery information;
• confirm which physical disk contains Windows;
• make sure the machine can boot Windows normally.

If the data matters, assume a disk or partition mistake is possible and prepare accordingly.

BitLocker or Device Encryption must be turned off

The current Omarchy dual-boot documentation says its free-space installation method is not compatible with BitLocker while installing.

In Windows, go to the current Device Encryption/BitLocker controls and turn encryption off.

Then allow decryption to finish completely before continuing.

Do not merely click "off" and immediately reboot into the installer while decryption is still in progress.

Shrink Windows from Windows

Use Disk Management in Windows.

Find the appropriate Windows partition and choose Shrink Volume.

The amount you shrink becomes unallocated space that Omarchy can use.

Do not create a new Windows filesystem in that space afterward.

The goal is to leave it as unallocated space.

Boot the Omarchy installer

Create and boot the normal Omarchy USB installer.

The current Getting Started guide also requires the relevant Secure Boot/TPM firmware settings to be disabled for installation.

When the installer reaches disk selection, choose the disk that contains the unallocated space.

Choose Free space install

This is the decision that protects the existing Windows partition.

Select Free space install.

Do not select the full-disk option if Windows must remain on the drive.

Omarchy uses the available unallocated space and currently keeps LUKS encryption enabled by default.

Omarchy installs Limine as the bootloader

After installation, Limine becomes the Omarchy bootloader.

The current official dual-boot instructions use:

limine-scan

to detect and add other installed systems such as Windows Boot Manager.

Follow the prompts, then reboot and check the resulting menu.

Test both systems before declaring success

A dual-boot installation is not finished merely because Omarchy started once.

Verify:

1. Omarchy boots.
2. Windows appears in Limine after scanning.
3. Windows actually boots.
4. Windows sees its expected files.
5. Omarchy still boots after returning from Windows.

Do that before making additional partition or bootloader changes.

Encryption and firmware choices have consequences

Turning off BitLocker for installation changes the Windows security state.

If you plan to re-enable Windows encryption later, first understand how that interacts with your boot arrangement and recovery keys.

Likewise, do not casually restore firmware security settings simply because Windows previously used them if the current Omarchy documentation says the installed system requires a different configuration.

Use the current Omarchy manual when making those changes.

Keep recovery media available

A dual-boot system has more moving pieces than a single-OS machine.

Keep:

• a Windows recovery path;
• the Omarchy installer USB;
• important backups;
• recovery credentials.

That turns a bootloader problem into a repair job instead of a data emergency.

For USB creation and the standard installation flow, see How to Install Omarchy From USB.

For the system itself, see What Is Omarchy?.