However before you go exploring Windows 10 it’s time to make that final image backup. So reboot the computer, click on the Windows 8.1 icon to load Windows 8.1, then launch your backup software and create a backup of the entire drive.
After completing the image backup your USB drive should have 3 folders and look similar to that shown below.
Note: Should you need to restore Windows 8.1 or the Windows 10 Technical Preview you can just select the partition that you want to restore, no need to restore the entire drive.
If you are using Windows 8.1 for most of your work and just exploring Windows 10 then you should consider creating a “Scheduled” daily backup of the Windows 8.1 partition, or you can include both Windows 8.1 and 10 partitions if you like and have the available space on your external USB drive. Pick a time when you know the PC will be on but you’re not using it, Dinner time for example.