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Dual boot with Windows

You can keep Windows on the computer and boot into either it or Seva Client OS.

This is a complex and fragile setup

The supported setup is a dedicated machine for the panel. Dual boot is harder than a normal installation and breaks easily:

  • a partitioning mistake destroys Windows — with nothing left to restore it from;
  • a wrong setting breaks booting entirely: format the EFI partition and neither system starts anymore;
  • it stays fragile after the installation too: Windows updates, BitLocker left on, a BIOS settings reset — any of these can leave you with a black screen instead of a boot menu.

Everything to do with partitions and the bootloader is on you. If you are not prepared to deal with that, put the panel on a dedicated machine and do not start.

Back up anything important before you begin.

We have not tested this scenario

Dual boot has not been verified on our image. Everything below is common practice for Ubuntu systems, not an instruction we have validated. Proceed at your own risk.

The one rule​

Never pick the automatic installation.

The automatic install, ERASES THE WHOLE DISK entry does not ask which disk to use — it picks one itself and wipes it completely. Even with Windows on a different disk, the risk of losing it is real.

For dual boot, always use this entry:

Install Seva Client OS — manual partitioning, choose disk layout

It stops at the partitioning step and lets you decide what goes where. Everything else (drivers, the panel, configuration) still happens automatically.

The safest layout: Windows on one physical disk, Seva Client OS on another. The systems share no partitions, and later you can remove one without touching the other.

  1. Windows is already on the first disk (or install it first).
  2. Boot from the USB drive and choose manual partitioning.
  3. In the partitioner, select the second disk — the one you are giving to Seva. Check its size and model so you do not mix them up.
  4. Give that disk away entirely: create a root ext4 partition on it with the mount point /.
  5. Do not touch or format the Windows partitions. The EFI partition (small, FAT32, usually 100–500 MB) can be reused — but do not format it, or the Windows bootloader is gone.
  6. Continue the installation as usual.

Option 2: a single disk​

Windows and Seva share one disk. Trickier and riskier, but it works.

Prepare inside Windows​

Do all of this before booting from the USB drive.

  1. Turn BitLocker off (or at least suspend it). Otherwise, once the bootloader changes, Windows asks for the recovery key — and without the key your data stays locked away.

  2. Disable fast startup and hibernation. In an administrator command prompt:

    powercfg /h off

    Without this, Windows leaves the disk in a "frozen" state that Linux cannot touch.

  3. Free up space. Disk Management (diskmgmt.msc) → right-click drive C: → Shrink Volume. Leave at least 256 GB for Seva: the system, CS2, the Steam runtime and a 16 GB swap file all go there. Leave the space unallocated — do not create a partition.

Install​

  1. Boot from the USB drive and choose manual partitioning.
  2. In the unallocated space, create an ext4 partition with the mount point /.
  3. Point the existing EFI partition at /boot/efi — and uncheck the format box. Formatting it removes the Windows bootloader.
  4. Leave the Windows partitions (C:, Recovery) alone.
  5. Continue the installation.

Choosing a system at power-on​

The reliable way is the Boot Menu. Press F12 (or F11, F8, Esc, Del) right after power-on and pick:

  • Windows Boot Manager — boot into Windows;
  • ubuntu — boot into Seva Client OS.

Whichever system you use more often can be put first in the BIOS boot order.

If Windows is missing from the GRUB menu

Windows may not show up in the GRUB boot menu. Nothing is broken — it is still there, just pick it from the Boot Menu.

Things worth knowing up front​

  • Windows updates sometimes take the bootloader back, and the computer starts booting straight into Windows. Seva has not gone anywhere — pick it in the Boot Menu.
  • The panel is designed for a dedicated machine. In a dual-boot setup, everything to do with partitions and the bootloader is on you.
  • Do not skimp on space. CS2 and the Steam runtime take tens of gigabytes, and running out of disk mid-installation is no fun.

To remove the panel and leave the machine with Windows only, see Removal and back to Windows.