Dual boot with Windows

You can install BioKids without erasing Windows: you free some space in Windows, BioKids installs into that space, and the computer asks which one you want at every start. Half the steps happen in Windows, half in the installer.

Before you start

• Back up your important files (an external disk or the cloud). Changing partitions always carries a small risk.
• At least 40 GB free on the Windows disk.
• If BitLocker is used, have the recovery key at hand (in your Microsoft account: aka.ms/myrecoverykey).
• Plug a laptop in. Have the BioKids USB stick ready: make a USB stick.

Prepare Windows

1. Suspend BitLocker (if it is on)

   Open Control Panel → BitLocker Drive Encryption. If BitLocker is on for C:, press Suspend protection, so changing the boot settings does not make Windows ask for the recovery key. Afterwards, press Resume protection in the same place.

   Cannot find that page (for example "Device encryption" on Windows Home)? Write the recovery key down anyway.

2. Turn off Fast Startup

   With Fast Startup on, Windows never fully shuts down and leaves its disk half open. Turn it off: Control Panel → Power Options → Choose what the power buttons do → Change settings that are currently unavailable → untick Turn on fast startup → Save changes.

   System Settings— ▢ ✕

   Shutdown settings

   Turn on fast startup (recommended)
   This helps start your PC faster after shutdown.

   Sleep

   Hibernate

   Lock

   Save changesCancel

3. Find out how Windows starts

   Press Win + R, type msinfo32 and press Enter. In System Information look at BIOS Mode: UEFI or Legacy. You will choose the USB stick to match it in a moment.

   Item	Value
   OS Name	Microsoft Windows 11
   System Type	x64-based PC
   BIOS Mode	UEFI
   Secure Boot State	On

4. Shrink Windows

   Right-click the Start button and open Disk Management. Right-click C: → Shrink Volume…. In "Enter the amount of space to shrink in MB" type at least 40960 (40 GB; more if you like) and press Shrink.

   Shrink C:✕

   Total size before shrink in MB:242688

   Size of available shrink space in MB:118312

   Enter the amount of space to shrink in MB:40960

   Total size after shrink in MB:201728

   ShrinkCancel

   A black-striped Unallocated area appears next to C:. Leave it alone; BioKids goes there.

Install BioKids

1. Start from the stick, in the same mode as Windows

   Plug the stick in, restart, and keep tapping the boot menu key (often F12, F11, F9, F8 or Esc). If BIOS Mode was UEFI, choose the stick entry starting with "UEFI: …"; if it was Legacy, the one without "UEFI".

   Boot Menu

   • Windows Boot Manager
   • UEFI: USB Flash Disk 1.00
   • USB Flash Disk 1.00

   ↑↓ select · Enter boot

   Secure Boot can stay on: BioKids uses Debian's signed boot loader. If your computer still refuses the stick, turn Secure Boot off in its settings.

2. "Start installer", language, keyboard and your account

   Choose Start installer in BioKids' menu. Choose the language and keyboard and create your parent account (name, username, password). These steps are the same as in the install guide.

3. Choose "use the largest continuous free space"

   On Partition disks, choose "Guided - use the largest continuous free space". It installs only into the space you freed in Windows: nothing outside that space is touched.

   

   Partition disks

   Partitioning method:

   Guided - use the largest continuous free space

   Guided - use entire disk

   Guided - use entire disk and set up LVM

   Guided - use entire disk and set up encrypted LVM

   Manual

   Go BackContinue

   Accept "All files in one partition", check on the summary that new partitions are made only in the free space, and confirm writing the changes.

4. Wait, take the stick out, restart

   Copying needs no network and takes 20–40 minutes on most computers. When it is done, take the stick out and press Continue.

5. The boot menu: BioKids or Windows?

   From now on the computer shows a menu for 5 seconds at every start. Press nothing and BioKids starts; to go to Windows, choose Windows Boot Manager with the arrows and press Enter.

   • Debian GNU/Linux
   • Advanced options for Debian GNU/Linux
   • Windows Boot Manager (on /dev/nvme0n1p1)
   • UEFI Firmware Settings

   ⏱ 5 s · ↑ ↓ · Enter

   When you sign in, the setup wizard opens. Not in Turkey? Set your time zone afterwards, as in the install guide.

6. Put a password on Windows

   BioKids does not supervise Windows. Your child could pick Windows in the menu, so give your Windows account a password (or PIN) your child does not know. If you suspended BitLocker, press Resume protection now.

Change your mind later? You can remove BioKids and go back to Windows only: back to Windows.

Something wrong?

sudo update-grub