Steam Deck is out of space

Updated: 2026-08-25

On a 64 GB or 256 GB Deck the games are rarely the whole story. Shader caches, Proton prefixes and old Proton builds add up quietly, and none of them are shown on the storage screen.

Start with what Steam will do for you

Before anything else: Settings → Storage in Game Mode lists installed games by size and moves them between the internal drive and a microSD card. A 512 GB card costs less than an hour of this and solves the problem outright for most people.

What follows is for the space that screen does not account for.

What is actually taking the room

Shader caches, one per game	`~/.local/share/Steam/steamapps/shadercache/<appid>`
Proton prefixes, one per game	`~/.local/share/Steam/steamapps/compatdata/<appid>`
Proton builds, one per version ever used	`~/.local/share/Steam/steamapps/common/Proton*`
Downloads that never finished	`~/.local/share/Steam/steamapps/downloading`
Workshop content	`~/.local/share/Steam/steamapps/workshop`
Mesa's own shader cache	`~/.cache/mesa_shader_cache`
Flatpak apps installed in Desktop Mode	`~/.var/app and /var/lib/flatpak`

A microSD card carries its own copy of the first five. Check both.

Safe to clear

Shader caches. Rebuilt on demand, at the cost of some stutter the first time you play. See what a shader cache is.
~/.cache/mesa_shader_cache. Same thing at the driver level, and it can run to several gigabytes on its own.
Old Proton builds in steamapps/common that nothing is set to use. Steam keeps every version it has ever downloaded; each is roughly 400 MB.
Unfinished downloads for games that are not installed.
Workshop content for games you have removed.

Check before clearing

Proton prefixes (compatdata) hold save files. For any game not covered by Steam Cloud, that folder is the only copy. Deleting a prefix for an uninstalled game is usually right and occasionally expensive — read what is inside one first.

Also worth leaving alone: anything under ~/.steam that you cannot identify, and the Flatpak runtimes shared between Desktop Mode apps — removing a runtime that something still needs means reinstalling both.

Doing it in Desktop Mode

Hold the power button and choose Switch to Desktop.
Open Dolphin, then View → Show Hidden Files, because everything above lives under a dotted folder.
Navigate to /home/deck/.local/share/Steam/steamapps and sort by size.
For shadercache and compatdata, the folder names are app ids — look one up at store.steampowered.com/app/<appid>.
Empty the trash afterwards. Dolphin moves rather than deletes, and on a full drive that frees nothing at all.

The last step catches more people than the rest of this page put together.

Act on it

Vapor Storage Manager has a native Linux build that runs on the Deck in Desktop Mode. It reads every library including the microSD card, turns the app ids into game names, and separates what rebuilds itself from what holds saves — which is the part that is genuinely hard to do by hand.

Download Vapor Storage Manager