How to Dual Boot Windows 8 and Windows 7

Generally when a new operating system version is released, people are timid about making the leap to upgrade to the new version. Many people want to take some time to try the new version while retaining access to their old files and folders on the older release.

This post will cover how to dual boot Windows 8 RTM and Windows 7. Before trying this procedure, be sure to back up your data in case something goes wrong.

To start out, I have a Windows 7 installation on a 120 GB disk. My Windows 7 files and data are only taking 20 GB or so and I want to create a partition to install Windows 8 using 50 GB (Note that the minimum recommended size is 20 GB, but I usually prefer 40-50GB). First, access the disk manager using mmc or by typing the following

1. Windows key + R to access the run prompt
2. Enter "diskmgmt.msc" and press enter

You can also use the search bar in the start menu,


Once you are in disk manager, right click the partition that belongs to Windows 7 and click "Shrink"


After you click shrink, specify 50 GB or whatever size you actually want (20 GB is the recommended minimum). Note that 50 GB = 51200 MB.



Click Shrink to start the shrinkoperation on the volume

Now that we have space for a 50 GB volume, restart and boot off of the Windows 8 DVD or Bootable USB Media.


We go through the installation procedure as follows. Select your regional settings and click next,



Then click "Install now"



Accept the EULA and start a Custom Installation,



Select the 50 GB of unallocated space that we created and click next



Wait for the install to complete (or grab a cup of coffee or a donut)...



After the reboot, the boot loader should show the older Windows release and the new Windows 8 option that we just installed.



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Navigating the Windows 8 User Interface
How to Create USB Windows 8 Installation Media (also works for Windows Server 2012, Windows 7, Windows Server 2008 R2)