Turns off in-process esync primitives. Worth trying for games that hang or crash under Proton.
Proton-Deck
Valve ProtonAdded Jul 8, 2026Last checked Sep 13, 2026Also documented for this game on ProtonDB · checked Oct 19, 2026
Safe
PROTON_OLD_GL_STRING=1 %command%Copy
Shorten the GL extension string (Linux, Proton)
Effect
Limits the reported OpenGL extension string length, for old games that crash when it is very long.
Proton-DeckDisplay
Valve ProtonAdded Jul 9, 2026Last checked Aug 12, 2026Also documented for this game on ProtonDB · checked Oct 19, 2026
Safe
PROTON_USE_WINED3D=1 %command%Copy
Use wined3d (OpenGL) instead of DXVK (Linux, Proton)
Effect
Routes d3d11, d3d10 and d3d9 through OpenGL-based wined3d rather than Vulkan-based DXVK. Usually slower; a fallback where DXVK fails.
Proton-DeckDisplay
Valve ProtonAdded Jul 9, 2026Last checked Sep 13, 2026Also documented for this game on ProtonDB · checked Oct 19, 2026
Safe
How to apply a launch option on Steam
Open Steam and go to your Library.
Right-click the game and choose Properties.
On the General tab, find the Launch Options field.
Type or paste the option (e.g. -windowed) into the field. To use several at once, separate them with spaces (e.g. -windowed -novid).
Close Properties. Steam saves automatically, and the option applies next time you launch the game.
To remove one, reopen the same field and delete the text. Options are game-specific; an option that helps one game may do nothing (or misbehave) in another.
Worth knowing: a launch option can break a game's rendering, reset local settings, or trip anti-cheat in multiplayer. Read the description first, add one at a time, and treat anything rated above Safe as a deliberate experiment.
