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Install Dual-Boot of a second Windows 8 on a Windows 8 computer (one Win8 installed first)

Last reviewed: July 2013

Introduction

This guide shows how to correctly and safely create a natural dual-boot of Windows 8 and another Windows 8 on a computer with a Windows 8 already installed. You can then run either of those two Windows by selecting one from a menu during bootup. No data loss will occur and a third-party boot utility is not used.

In this procedure you need to resize the Windows 8 drive to make room for another Windows 8 unless you happen to have free disk space or you install Windows 8 on a second hard disk. This example uses a single hard disk.

A 64-bit Windows 8.1 was used in testing and another Windows 8.1 was added. The computer used was a 64-bit Dell Studio XPS 8100 (2.93 GHz), Core i7, 8 GB RAM DDR3, NVidia GeForce GTX 460, 1 TB SATA hard disk (not using GPT/UEFI).

The procedure used is quite easy and suitable for most users.


Important Installation Notes

Full Installation CD/DVDs. The Windows you are adding cannot be installed from a Recovery partition or Repair CD/DVD provided by some OEMs. You need the full installation version to install a Windows.

Shrinking a Windows 8, 7 or Vista drive. You should use Shrink in Windows' Disk Management to resize the Windows partition. You can read Shrink the Windows 8. 7 or Vista Partition for instructions on completing this task successfully. Use the free GParted Live CD to gain disk space only if you must - read the page Use GParted to Resize the Windows 8, 7 or Vista Partition to learn how..

SUMMARY of Procedure (Advanced users)

  1. Backup important data.
  2. Create Unallocated space for Windows 8 at end of Windows disk (use Shrink) or use a second hard disk (using GPT if appropriate).
  3. Boot from Windows 8 DVD, select Install, then Custom, and install Windows 8 on the new Unallocated space.

That's it! The Windows boot loader menu now allows booting to Windows 8 and a second Windows 8.

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Details: Create a Dual-boot with a second Windows 8 when Windows 8 is already installed

Installing other operating systems on your Windows 8 computer may invalidate your warrantee.
It's important to follow the instructions exactly as stated and you should start with a properly working Windows.


Make your preparations

  1. Make sure you can boot from a bootable CD/DVD
  2. Backup important data before making any changes to a partition. You can burn files to a DVD, clone an image of your hard disk, copy files to a USB flash/pen/thumb drive, or use an USB external drive (a good choice)
  3. Disconnect all unnecessary external devices before you start.

Make free space (Unallocated) for the new Windows 8

The Windows 8 drive is resized using Shrink in Windows' Disk Management leaving Unallocated space at the end of the disk (to the right).

Always note the size of each partition and also label each (this guide uses wn_8 and wn_8_2).
You can use a second hard disk for Windows 8 but it should use the new GPT Partition Table if the first disk uses GPT.

  1. Restart computer correctly (close all programs before you Restart computer).
  2. Open Disk Management in Windows 8 (press Win and X keys, click Disk Management).
    • Optional: Right-click your CD/DVD drive(s), select Change drive letter and paths..., and click Change.
      Change the drive letter to K (get it out of the way!).
    • Right-click the Windows 8 Volume (probably C:), and select Properties.
      In the General tab, enter wn_8 as the label for the Windows 8 volume, and click Apply.
  3. Still in Disk Management in Windows 8
    • Right-click the wn_8 volume, and click Shrink Volume.
      • In Enter the amount of space to shrink in MB:, enter enough windows 8.
      • Click the Shrink button (it may take some time!).
        Note that we will leave the newly acquired free space as Unallocated.
      If Shrink does not give you sufficient Unallocated space, read how to Shrink the Windows 8, 7 or Windows Vista Partition for instructions or use the free GParted Live CD. Then return here.
  4. Restart to Windows 8.
    • Open Disk Management and check that the change made is correct.

Now Install Windows 8 when Windows 8 was Installed first

  • Bootup from the Windows 8 installation DVD.
    • Select your Language, and Time..., and click Install now.
    • In Which type of installation do you want? select Custom (Advanced).
    • In Where do you want to install Windows? select the Unallocated area prepared earlier.
  • Restart your computer when installation is complete. Select the top Windows 8.
    (The new Windows 8 is the default in the menu).
    In File Explorer, label the new Windows 8 drive as wn_8_2 (right-click the Win8 drive and select Properties).

Congratulations! You have created a natural dual-boot of Windows 8 and Windows 8 when Windows 8 was installed first.

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Repair Windows 8 Boot Menu and Startup

Some users claim that the Windows 8 GUI boot menu can occasionally go missing! This simple procedure will return that graphical menu:

  1. Boot to the first Windows 8.
  2. Hold down both the Win and X keys and then press the A key (to open an elevated Command Prompt).
  3. Run this command at the prompt:
    bcdboot c:\windows
    where C is the letter allocated to this Windows 8 (change the C if necessary).
  4. Reboot. The Windows 8 GUI boot menu is back!

This Windows 8 is the default boot. You can alter this in Change defaults or change other options on the boot menu.


If you ever need to do a fuller repair of the Windows 8 startup, you should do the following:

  1. Bootup from your Windows 8 DVD to the first screen ("Windows Setup").
  2. Hold down the Shift key and tap F10 (to open a Command Prompt).
    Type in these commands and press Entry after each (note the space after each BOOTREC):
    bootrec /fixmbr    - to update the Master Boot Record - just in case!
    bootrec /fixboot    - to recreate the Win8 Boot Sector of the system partition
    bootrec /rebuildbcd    - to rebuild the BCD data & boot menu or just add a compatible Windows to the menu
    exit
  3. Exit the installation now and reboot.

Note: The Bootrec command has not been tested on the newer (U)EFI / GPT systems.

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Please remember that you alone are responsible for the consequences of any changes you make to your computer hardware or software.

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