The original poster is attempting to create a Windows 10 boot drive on a large external USB but encounters an error at 30% during media creation, citing insufficient space despite reformatting the drives. A respondent explains that Windows 10 typically doesn't support booting directly from external drives, although some hacks exist, but they are unreliable, whereas Linux distributions like Ubuntu and Mint are well-suited for running from USB external storage. The overall sentiment suggests that creating a Windows 10 boot drive from an external USB is problematic and not straightforward.
There are some hacks that some people here have gotten to work that way; but it's not reliable in my opinion as well as not recommended. Linux versions such as Ubuntu and Mint do an outstanding job of running from USB external storage devices; and run in memory and you don't have to install the OS onto the boot drive if you don't wish to.
