Once you make your drive selection (in this case, G: (Untitled)), the Windows Media Creation tool will start working its magic, downloading Windows 10 and writing it to the USB in a way that makes it bootable from your Steam Deck (or any other computer for that matter). If it still doesn't show up, you may need to reformat the drive or the drive might be too small, or worse, damaged. If you don't see yours, click that 'refresh drive list' option until it pops up. Hit next and it will bring up a list of removable drives. The next step is pretty obvious: select 'USB flash drive.' You need to select Windows 10 in the Edition options on the next screen, because currently Steam Deck doesn't support Windows 11 installations. You're going to want to select 'Create installation media (USB flash drive, DVD, or ISO file) for another PC' Once you've downloaded the Windows Media Creation tool, open it up and follow the instructions.

You might be able to get away with using a microSD card in a USB adapter, if the Windows tool recognizes it as a USB device.

Start by visiting this page (click here) to create a bootable Windows USB. USB-C Hub (optional: with Ethernet port).

Steam offline installer windows 10