When you don’t have (or don’t want) CDs or DVDs.
Sometimes, such as when your computer won’t boot, or you’re attempting to install a new operating system, you need a bootable thumb drive from which to start the machine. But you can’t just copy an ISO file to your thumb drive and expect it to work.
ISO files1 contain a media image: a complete copy of a disc’s contents, including the information needed to boot. If you were installing a new operating system, for example, you’d download the ISO file, burn it to optical media, and boot from that CD or DVD.
Downloading ISO files onto USB thumb drives is the replacement. But just like you need to “burn” an ISO to optical media, there’s a process to putting an ISO onto a USB thumb drive so it will be bootable. While it’s also often referred to as “burning”, it’s something completely different.
There’s an app for that. Rufus to the rescue.
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Creating a bootable thumb drive from an ISO
Just copying the ISO onto a thumb drive won’t work. Use Rufus to “burn” an ISO onto a USB thumb drive so it can boot your computer. Rufus sets up the thumb drive with the structure needed to boot. Download Rufus, select your thumb drive, pick the ISO, and click START. Beware: all data on the thumb drive will be erased.
You can’t just copy
One of the first mistakes people make is to copy an ISO to a thumb drive they have lying around.
The problem is that copying a file from disk to a thumb drive (or from anywhere to a thumb drive) doesn’t set up the additional overhead to make that thumb drive bootable. It’s just a disk with a large file on it, nothing more. It’s a fine way to copy the ISO file to another machine, but it’s not something you can boot from.
That requires an additional step.
Rufus
Rufus is available from https://rufus.ie.
Important: Ignore all the “Download” buttons. The vast majority are ads and will not download Rufus. (This is unfortunately true for many sites.)
Instead, scroll down until you find the list of “lastest releases” installation links.
In most cases, the first one — Standard installation for 64-bit Windows — is all you need.
Download and run it.
Using Rufus
Under Drive Properties, click on whatever is listed under Device (if anything).
This lists all of the USB thumb drives Rufus has found that it could write to. In my case above, there is only one. If you do not see your thumb drive listed, make certain it’s inserted. The list should update after you insert the device. Note that Rufus writes to thumb drives, not to external hard drives. The latter will not appear in the list even if an external drive is connected.
Select the thumb drive you want to write to.
Leave Boot selection unchanged as “Disk or ISO image (Please select)”. Click the SELECT button.
Your choices are SELECT and DOWNLOAD.
- SELECT opens a standard file-open dialog box that alloww you to select the ISO you’ve previously downloaded to be burned.
- DOWNLOAD gives you a list of common ISOs you can have Rufus download for you. It’s always been a very short list for me.
I recommend you download the ISO you want separately before running Rufus so you know exactly what you’re getting.
You’re ready to start.
You have a thumb drive selected to write to and an ISO file selected to write. Click START.
Windows 11 tweaks
If you’re burning a Windows 11 ISO, as I show above, you may be presented with a dialog of enticing tweaks you can make to the installation.
Many of these options are commonly requested changes for Windows 11 that can be difficult to accomplish after installation. Whenever you use this thumb drive to install Windows, these customizations will be made automatically.
Note that each of these changes the ISO as it’s written. And, of course, Microsoft may change Windows 11 such that these stop working. As always, use such tweaks at your own risk; you needn’t choose to use any of them.
If anything fails on the eventual Windows installation, repeat this process and deselect all the items before trying again.
Everything will be erased
You’ll get a warning.
Make certain that the correct device is displayed and that there’s nothing on it you need to save elsewhere. The entire thumb drive will be erased.
Click OK to begin the process. When complete, you’ll have a bootable USB thumb drive based on the ISO you selected.
Check your thumb drive
A quick view of the thumb drive’s contents should show you what you would expect to find on normal installation media: lots of files.
You can now boot from this USB thumb drive.2
Do this
Particularly if the machine you want to install something on has no CD or DVD drive, you can now easily use a USB thumb drive in its place.
And if you’re dealing with Windows 11, you even have some nifty tweaks you can make along the way.
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Footnotes & References
1: ISO stands for International Organization for Standardization. Even though it’s a very generic term, and is used in many other places and ways, “ISO” has become the standard way to reference a disk image in an ISO-specified format.
2: Exactly how you do that varies based on your machine. It’s typically a UEFI or BIOS setting called “boot order”. You can change it, if needed, to check USB devices for bootable operating systems before checking the hard disk.
Your footnotes and associated links aren’t fully working. Toward the end of the article have a footnote #2, but there is no footnote #2 in the bottom list of footnotes – only a footnote #3, which doesn’t have a corresponding reference in the article. You probably meant to use “#2” in the list instead of “#3”.
Thanks. Good catch. Fixed now.
Rufus is also available through the Microsoft Store, along with Sysinternals Suite.
Two points:
1. HP laptop Touchpad was not recognized during attempted clean install using Rufus. Unable to click the box acknowledging that SDD would be wiped clean. Resolved by installing a wired mouse. (did not try wireless mouse)
2. Rufus USB must be removed before Windows restarts after installing. If not, you’ll get to do the install all over again ; )
Understand that it’s not a “Rufus USB”. Rufus is simply a tool to create a bootable USB from an ISO. Presumably this is a Windows installation, so the issues would be the Windows setup on that USB.