Valve has pushed Marvel Rivals back onto Proton Hotfix by default on SteamOS and Linux after a newer Proton build caused the game to stop working properly. The change means players on Steam Deck and other Linux systems should be able to launch the game again without manually forcing a compatibility layer.
The fix arrives alongside the game’s latest major update, Season 9, and Valve’s adjustment is already visible through SteamOS and Big Picture Mode. GamingOnLinux reports that Marvel Rivals is now assigned to Proton Hotfix automatically, which is the practical change most players will notice: the game should pick the corrected Proton build on its own instead of relying on a user-made workaround.
Marvel Rivals now defaults to Proton Hotfix on SteamOS
For players who previously set a custom Proton version or added launch options to get Marvel Rivals running, those manual settings are no longer needed. Removing them should let Steam pick Proton Hotfix automatically the next time the game is launched.
If Proton Hotfix is not already installed, Steam will download it when required for supported games. That matters for SteamOS users because the fix is not tied to a separate game patch on the player’s side; it is part of Valve’s compatibility layer handling on the Steam client side.
Valve does not usually publish detailed public notes for Proton Hotfix changes, so the clearest sign of the update is the game’s new default compatibility setting. In this case, that change is enough to restore normal startup behavior for a title that had recently broken under newer Proton builds.
Season 9 is the update tied to the compatibility fix
The timing is important because the issue appeared with Marvel Rivals’ constantly updated live-service build. Valve’s correction is described as working again with the game’s latest major update, Season 9, rather than being a broad promise for every future build.
That makes this a useful reminder for SteamOS and Linux players of live-service games: a game can work one week and fail the next if a new update changes something Proton does not yet handle cleanly. In this case, Valve has already stepped in, but the need for a hotfix shows how dependent these games still are on compatibility-layer updates when developers change their software stack.
Valve recently had to make a similar fix for Diablo IV, which suggests the company is still responding game by game when newer Proton versions expose compatibility problems. Marvel Rivals is simply the latest high-profile example.
What Steam Deck and Linux players should check now
If Marvel Rivals was broken on your SteamOS or Linux setup, the first thing to check is whether the game still has any manual Proton override attached to it. If you forced a specific Proton version or added launch parameters to work around the issue, removing those settings should let the game use Proton Hotfix automatically.
- Check the compatibility setting in Steam for Marvel Rivals.
- Remove manual Proton selections if you added them earlier.
- Clear any custom launch options tied to the workaround.
- Let Steam download Proton Hotfix if it is not already present.
The broader takeaway is straightforward: Valve has repaired the Linux-side breakage, but the fix lives in Proton rather than in the game itself. For Steam Deck owners and other Linux gamers, that means the next launch should be simpler than the last one, with fewer compatibility tweaks needed just to get into the game.
Source: GamingOnLinux. Official game page: Marvel Rivals on Steam.