Installing Ubuntu on a second drive lets you keep Windows on its own disk, but the setup still depends on one decision: start the installer in the same firmware mode that Windows uses. This walkthrough shows how to install Ubuntu without selecting or formatting the Windows drive, then choose either Ubuntu or Windows from the computer’s boot menu.
What this setup changes
Each operating system keeps its filesystems on a separate physical drive. Ubuntu still creates a boot entry in UEFI firmware, so the choice between operating systems normally happens in the firmware boot menu or through the Ubuntu bootloader.
Check these conditions before you start
- Back up data from both drives. Partition changes can destroy data when you select the wrong disk.
- Use a USB installer made from the current Ubuntu Desktop image. The Ubuntu download page is the source for the current release.
- Confirm whether Windows starts in UEFI mode. Open System Information in Windows and check BIOS Mode. Boot the Ubuntu USB in UEFI mode when Windows uses UEFI.
If you need the installation USB first, use the LinuxForDevices bootable USB instructions. Keep the Windows drive connected only if you are comfortable identifying its capacity and partitions in the installer.
Install Ubuntu on the second drive
Start the USB installer from the firmware boot menu, not from inside a running Windows session. Choose Try or Install Ubuntu, then continue until the installer asks where Ubuntu should go.
At the storage screen, choose the second physical drive by its size and model. Do not select the Windows drive.
If the second drive is empty, let Ubuntu use that drive. If it contains files, choose manual partitioning and leave every Windows partition unchanged.
Use manual partitioning when the second drive has data
Create an ext4 partition mounted at / for Ubuntu. You can create a separate home partition if you want personal files apart from the operating system, but it is optional.
On UEFI systems, Ubuntu needs an EFI System Partition. You can use the existing EFI System Partition without formatting it, or create one on the Ubuntu drive. The important boundary is that the installer must not format the EFI partition that Windows uses.
Choose the operating system at startup
After the installation restarts, open your computer’s one-time boot menu and select Ubuntu or Windows Boot Manager. If Ubuntu starts by default and you want Windows first, change the firmware boot order rather than deleting either boot entry.
Ubuntu can also show Windows in its boot menu. If Windows is missing, first confirm that both drives are visible in firmware. Then boot Ubuntu and repair the boot configuration only after you have verified the Windows entry remains available.
Verify the installation before relying on it
- Boot Windows from the firmware boot menu and confirm its files are intact.
- Boot Ubuntu and open Disks to confirm the Ubuntu filesystem is on the intended drive.
- Restart twice and confirm both operating systems remain selectable.
Useful Ubuntu follow-up tasks
Once both systems boot, keep Ubuntu updated before installing development tools. You can compare Ubuntu and openSUSE if you are still deciding which distribution belongs on the Linux drive, and use the VMware Tools setup guide if Ubuntu will run in a virtual machine instead.
For a desktop that changes the Ubuntu experience without replacing the base system, see the Kubuntu and Ubuntu comparison.
Can Ubuntu and Windows use separate drives?
Yes. Install Ubuntu to the second drive and do not format the Windows drive or its partitions.
Should Ubuntu and Windows use the same boot mode?
Yes. Use UEFI for both when Windows is installed in UEFI mode, so firmware can find both boot entries consistently.