How to dual-boot Windows 10 with Windows 8.1 or 7

For customers who want to try Windows 10 without replacing their current Windows 8.1 or 7 installation, it’s actually possibly thanks to Microsoft’s Windows 10 media creation tool. The tool allows customers to create bootable media in the form of an ISO, DVD, or USB recovery drive. This tool can also be used to install Windows 10 as a dual-boot option beside your current Windows 8.1 or Windows 7 installation.

The downside to dual-booting Windows 10 as opposed to upgrading is that it won’t be activated. This means that users won’t be able to personalize their Windows 10 installation and a watermark will be on the bottom right corner asking you to activate. But it’s still good that you can try Windows 10 and make sure it works on your PC before you upgrade.

Before you dive right in, we don’t recommend this guide to users who aren’t familiar with BIOS or partitioning. But if you insist, be sure to do a little research before attempting this without knowing what you’re doing. Without further ado, let’s get started.

1. Download the Windows 10 media creation tool from this link.
2. Open the Control Panel and navigate to System and Security > Create and manage hard disk partitions. Right click on the partition your Windows 8.1 or Windows 7 is installed on (that’s the big C: partition) and click Shrink Volume, then enter the amount you want to shrink for Windows 10.
   
3. Now right click the empty volume you just created and click Create Simple Volume, then set the volume format to NTFS.
   
4. One you have your Windows 10 volume created, open the Windows 10 media creation tool you just downloaded. Click Create installation media for another PC and select the language and version of Windows 10 you want to install. Refer to the chart below to decide which version you want to install.
5. Create the installation media.
   
   1. If you want to install Windows 10 from a DVD, click ISO file and save it where you want. After the ISO file is created (it will take a while to download Windows 10), insert your blank disc into the DVD drive. Open the ISO file you just created with Windows Disk Image Burner and burn it onto the blank disc.
   2. If you’re installing from a thumb drive or SD card, click USB flash drive. Plug in your thumb drive and select the device from the media creation tool.
      
6. Boot from the thumb drive.
   1. If you’re running Windows 8.1, go into Settings > Update and Recovery > Recovery then under Advanced Startup and click Restart now. One your PC is on the recovery screen, click Use another operating system and then click the device you put your Windows installation onto.
   2. If you’re running Windows 7, go ahead and shut down your computer. Startup into the boot device menu by pressing the power button and the key your PC manufacturer set for this function (this could be ESC, DEL, or F1-F12, refer to PC manual for help). Select the device you put your Windows installation onto.
7. From the Windows 10 setup screen, select the language and edition of Windows you want to install. You can skip entering the product key if you’re only trying Windows 10, or enter one if you recently purchased it. From the “Which type of installation do you want?” screen select Custom: Install Windows only (advanced). Select the device volume you created for Windows 10, and click next. Windows 10 will now install onto your PC.

One it’s done, restart your PC and follow the on screen instructions to setup your Windows 10 PC. Every time you restart, you can choose between your current Windows installation and Windows 10. And if you decide you want to continue dual-booting as opposed to upgrading, it’s easy to buy the full version of Windows from the Store app.