It takes about 10–15 minutes for the copy to finish. When it’s done, your external hard drive is now a Windows installation drive.
Here’s a short, narrative-style guide based on the phrase — told as if you’re the one doing it. You’ve got a laptop with a broken internal drive, or maybe you just want a fresh Windows install without burning a DVD or making a USB stick from scratch. All you have is an old external hard drive and a Windows ISO file. install windows from external hard drive
Some older computers won’t boot from an external hard drive via USB. And if your external drive is slow (5400 RPM), the initial boot to setup might take a minute or two. But once the Windows installer loads into RAM, speed is fine. It takes about 10–15 minutes for the copy to finish
You plug the external hard drive into a working computer. It’s 500 GB, mostly empty. You know Windows setup won’t need all that space, but the drive has to be bootable. You’ve got a laptop with a broken internal