Windows bootable USB

I recently used a script (Integrate7 script) to slipstreamed all updates into Windows 7 pro - the resulting ISO was nearly 5gb. I wanted to burn it to an USB, but got a warning that the USB may not be bootable.
I searched your documentation and this forum and came across an article that you Don’t recommend using ‘Balena’ to burn Windows to USB, but I’m almost sure I did burn an ISO of Windows 7 pro to USB using BalenaEtcher about 18 month ago but I did not get the warning? and it installed on a laptop without problem? The ISO is an official one from Microsoft. I always thought that an ISO of an OS is always bootable.
Has something changed in the way ‘Etcher works’ over the last 2 years?
The slipstreaming is done in Windows 7, but the ISO to USB burning is done in Linux (Mint, or Manjaro)
The slipstreamed Windows 7 is intended for installing Windows 7 in ‘VirtualBox’ under Linux.

Hi there, Etcher does not support creating bootable USB media. You can try following this guide (for macOS) to create a bootable Windows USB stick from an image file.

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Whats really interesting is is I can make a windows 10 installer USB drive if I use the clone drive option and clone a drive that was flashed using the Windows media creation tool. So in some way Etcher is treating ISO files differently then physical drives. That’s not very good because having to clone from a drive takes up a bit of the USB host bandwidth and slow down the write speeds. Too bad because I was thinking about buying the Etcher Pro for making Windows 10 installer USB drives in bulk.

Hi, Jacob,

Sorry, we don’t have a better answer for you, but essentially, Windows does some black magic voodoo when flashing the ISO. You can read more about the challenges with flashing a bootable USB drive here.

We will probably support this feature in the future, but we are currently undergoing a major structural change to etcher, which will actually make this implementation somewhat easier.

So, check back, but for now, I would recommend using Rufus when flashing bootable ISO’s.

You can of course clone a drive as you mention, because the .wim file is already split.

We will eventually get to this, but for now, we appreciate your patience.

PRs welcome btw! Even just a proof of concept flashing an ISO on a linux machine would probably be helpful for us to integrate into etcher.

ab77, many thanks! Your information led me to the answer I was seeking. I followed the guide you linked, and it worked flawlessly!


Hi there, Etcher does not support creating bootable USB media.

Are you sure about that? Because that’s literally your whole thing. That’s literally what Etcher does.

Does flashing ISO files to USB drives to make them BOOTABLE USB DRIVES not sound like what Etcher does??