How to Install Windows 10 on an External Drive for Mac
If you’re a Mac user, you’ve probably run into those few softwares that are Windows only. Virtual machines are great for quick Windows tasks, but they lack power and are quite slow. If you have an extra hard drive laying about, you can turn it into a small Windows computer that you just plug and boot.
I’d recommend using an SSD or an external hard drive with a USB-C or USB3 connector, as USB2 can be a bit slow for this.
This process will take some time and maybe some troubleshooting, but it’s much more resilient to updates than Bootcamp and won’t mess up your internal hard drive. Also, be sure to back up your computer before trying this.