Windows 11 and Windows 10 are now installed, here’s how to ensure both can boot up properly.

Great — since both Windows 11 and Windows 10 are now installed, here’s how to ensure both can boot up properly.

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✅ Boot Mode: UEFI

You must set your firmware (BIOS/UEFI settings) to UEFI-only mode (not Legacy, not CSM). Both Windows 10 and 11 support UEFI and GPT — and they will dual boot only if your system is set to boot in UEFI mode.

Steps:

1. Enter UEFI firmware settings
   • Reboot your PC and press DEL, F2, F10, or ESC (depending on your motherboard or laptop brand).
2. Ensure these settings are configured:
   • Boot Mode / Boot Option: UEFI
   • Disable: Legacy Boot / CSM Compatibility Support
   • Secure Boot: Optional — can be Enabled (recommended for Windows 11), but not strictly required if you’re using unsigned drivers or older hardware.
3. Save and Exit, then boot.

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⛓ Boot Manager Behavior

After rebooting in UEFI mode:

• The system should automatically show a boot menu asking you to pick between Windows 10 and Windows 11.
• If it boots straight into one version, don’t worry — you can manually set the boot menu.

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🧰 Optional: Set Up Dual Boot Menu

If you don’t see a dual boot menu, Windows 10 likely overwrote the bootloader. You can fix it easily:

Option 1: Use bcdedit in Windows

1. Boot into either Windows (10 or 11).
2. Open Command Prompt as Administrator.
3. Run this command to see current entries:

4.  bcdedit

5. If one OS is missing, you can add it manually. For example, to add Windows 11:

6.  bcdedit /set {current} description "Windows 10"

7.  bcdedit /create {ntldr} /d "Windows 11" /application osloader

(We can guide this step-by-step based on what bcdedit shows on your system.)

Option 2: Use a GUI tool like EasyBCD

• Download and install EasyBCD.
• It lets you:
  • Rename entries
  • Choose default OS
  • Set timeout for menu
  • Fix bootloader if one OS doesn’t show up

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