Force the legacy OpenGL renderer (Unity games, legacy builds)
Effect
Windows only. Selects Unity's LEGACY OpenGL backend, not the core profile — use -force-glcore for that. Builds made with newer Unity versions may not carry the legacy backend at all, in which case this has no effect.
PCGamingWikiAdded Jun 27, 2026Last checked Sep 9, 2026
Safe
PROTON_USE_D9VK=1 %command%Copy
Use DXVK for Direct3D 9 (obsolete) (Linux, Proton 4.x and earlier)
Effect
Valve marks it obsoleted as of Proton 5.0 — DXVK became the default for d3d9, so on any current Proton this does nothing. In older versions it selected Vulkan-based DXVK over OpenGL-based wined3d.
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.
