How to format a microSD card on the Steam Deck
Wipe the slate clean. Then slap games on it
Knowing how to format a microSD card on the Steam Deck is as essential as the card itself. While the Deck is compatible with any microSD card that meets at least the UHD-I specification – loads, in other words – it doesn’t format them automatically, leaving one final DIY step before your expanded storage card can actually serve as expanded storage. It’s easily done, though, as the shortness of this guide attests.
Once your microSD is formatted, you can basically treat it as you would a fully-fledged SSD in a desktop PC: you can set it as the default drive for installing Steam games, rename it, and move individual games between it and your Steam Deck’s main drive. Or format it again, if (touch wood) there’s ever a technical problem with it. Or you just want to uninstall a bunch of games at once, in a slightly brutish fashion.
In any case, formatting only takes a few moments, and is (thankfully) nowhere near as complicated as replacing the Steam Deck SSD outright – your alternative route into embiggened handheld game storage.
How to format a microSD card on the Steam Deck
Step 1: Make sure your microSD card is fully inserted into the Steam Deck’s slot. Obviously.
Step 2: Turn on your Deck and press the Steam button to open the main SteamOS menu. Scroll down to and select "Settings".
Step 3: Enter the System section, then hit "Check For Updates" and apply if there’s one available. This isn’t always necessary, but there have been reports of Steam Deck owners being unable to format their microSDs unless the system is up to date, so handle that first.
Step 4: Once you’re on the latest software version, it’s time to format. There’s actually a "Format SD card" button right there in the System menu, though weirdly, I’ve found this doesn’t always work. For a more reliable method, leave the System menu and scroll down to the Storage section. Then, highlight your microSD card and press the Y button.
Step 5: Hit "Confirm" when prompted. If you want, you can rename the drive here before confirming, though you can always change it later as well. There’ll be one more window after this; just press “Confirm” again.
After a few seconds, your Steam Deck’s microSD will be formatted and ready to stuff to its tiny plastic gills with game installs. On which note, you may wish to set it as the default drive for Steam downloads as well – while you’re in the Storage menu, highlight the microSD and press the X button to make it the default. A little star should appear next to it, confirming the switch.
To rename the microSD (or format it again), press the Y button while it’s highlighted, just as you did when first formatting. And, if you want to move games from the internal SSD to the microSD (or vice-versa), highlight one the in the list of games, press Y, and make sure the other drive is selected as the destination. From there, just hit "Move", then "Close" once the transfer is complete.