To do this, head to the Startup Disk preference setting in Settings.Įvery time the Mac starts, you can also toggle between OS X and Windows by holding down the Option (Alt) key immediately upon startup. Once you have Windows installed, you can set the default OS that will start each time you boot your Mac. Set the Default Startup OS or Toggle Between OS X and Windows This ISO file is the disk image that you can burn to a USB or DVD. The Mac will need to restart to complete the process and will automatically boot into Windows 10 when it's done. Part 3 Create a New Partition for Windows OS on Mac. Rufus is one of several programs that allow you to create an ISO image on a USB stick. How to Create a Bootable USB using Rufus. This can be useful if you ever need to recover, repair or install an operating system on your computer. Follow the prompts to finish installing Windows. By running the bootable USB however, you can boot up your computer using the USB’s ISO image instead.