protonscr

Proton 9 and 10, games dont launch

protonclosed
ValveSoftware/Proton#8737 · opened 2025-05-26 by mathew2214 · updated 2025-06-04 · 11 comments · github
Mmathew2214 2025-05-26 github

Using deep rock galactic as my example here, but this effects all games ive tried.
using Proton 9 or newer, games do not launch. i can only play games by reverting to Proton 8 or older.

when trying to use newer proton, i get this popup:

Image

this happens on both Proton 9 and 10, to all games ive tested with. just using DRG as my example here because its known to work well with older proton versions.

system info: https://gist.github.com/mathew2214/4d0ddc4a738995b582bdc38576b6bc29

proton log from DRG: https://gist.github.com/mathew2214/b32287c04b545d7907fee54ab103502c

exact line of error log that's relevant reads:
171372.682:0134:0138:err:steamclient:steamclient_init unable to load Steam_IsKnownInterface 171372.682:0134:0138:err:msvcrt:_wassert (L"!status",L"../src-lsteamclient/steamclient_main.c",357)

Valve, please fix.

Mmathew2214 2025-05-26 github

i suspect this commit
https://github.com/ValveSoftware/Proton/commit/cf89fdf018d500dfacd80ce48f35733bbb2baef0?diff=unified#diff-721c03714e31f554fa890064479e8f9f9fa448ce1e940aa246b41020e36349d0L480
may be my issue. although the build instructions for Proton are incomplete or incorrect, so i cannot compile and check for myself.

keeps giving me the compile time error "configure: error: perl module 'JSON' not found. Please install the 'libjson-perl' package."

even though that package IS installed.

Aalasky17 2025-05-27 github

@mathew2214 Based on the logs you provided, it looks like the problem lies in your native steamclient.so which ships with Linux Steam, not Proton specifically. The commit seems to be a red herring :)

It sounds like your steam install is broken in some way - reinstalling Steam could be enough to fix whatever is going awry.

Mmathew2214 2025-05-27 github

if it is not a Proton problem, then why do native games and older proton versions not have this issue? if my steam client itself was broken, surely the problem wouldnt be isolated to newer protons.

i would love to be able to compile that specific commit of Proton, and then the one immediately previous to test my suspicion of that commit being the problem. but the instructions for downloading that specific revision of the source code are nowhere to be found, normal git commands for targeting that specific commit dont work.

if somebody has the compiling source code for experimental-9.0-20240221, i'd greatly appreciate it

Mmathew2214 2025-05-27 github

ive also observed the exact same behavior on my laptop, which is debian trixie, not bookworm like my desktop is. might just be an incompatibility thing with debian and newer protons?

i seem unable to recreate this issue on Steam Deck. does Valve no longer officially support Debian?

Mmathew2214 2025-05-27 github

trying to obtain the source code for experimental-9.0-20240221, i keep getting the error

Submodule path 'openvr': checked out '5e45960cf44d6eb19bbadcae4a3d32578a380c17' warning: redirecting to https://gitlab.winehq.org/wine/vkd3d.git/ warning: redirecting to https://gitlab.winehq.org/wine/vkd3d.git/ fatal: remote error: upload-pack: not our ref a16b9dffda9becb1dbcad476c38b78f2144f35b4 fatal: Fetched in submodule path 'vkd3d', but it did not contain a16b9dffda9becb1dbcad476c38b78f2144f35b4. Direct fetching of that commit failed.

is there any way for me to obtain the source code for experimental-9.0-20240221?

Aalasky17 2025-05-27 github

Have you tried git submodule --sync? https://gitlab.winehq.org is also a public git repository, so if you can't get your tree to sync up properly, you can manually add https://gitlab.winehq.org/wine/vkd3d.git as a remote for your vkd3d submodule and fetch that separately.

Proton utilizes the native linux steamclient.so file differently from native games. It could be that the way you are installing steam is leading to an outdated steamclient.so file.

Mmathew2214 2025-05-27 github

https://github.com/ValveSoftware/steam-for-linux/issues/9031#issuecomment-1487104498

this is how i have installed my Steam client. i have not changed anything about my steam client setup since. Proton has changed, my Steam client setup has not.

Aalasky17 2025-05-27 github

@mathew2214 Well that explains everything. Newer Proton versions rely on a newer steamclient.so version that is shipped with the current steam client. We stay in sync with each other -- using the new version of one thing requires the new version of the other :)

Mmathew2214 2025-05-27 github

i still intend to test if that specific commit is what breaks things. if i can prove that to be so, it should be trivial to simply undo the break and then port that fix to modern proton. right?

Kkisak-valve maintainer 2025-05-27 github

Hello @mathew2214, it's not reasonable to expect Proton devs to test against or support a random frozen old version of Steam. Steam changes over time and only the current non-beta and beta clients are supportable in general. Since Proton is an open source project, you may find a personal workaround, but you're going to progressively hit more quirks as time goes on.

I'm going to go ahead and close this issue report as won't fix.

Mmathew2214 2025-06-04 github

i grabbed the newer steamclient.so from my Steam Deck, and paced it into the places in my desktop. this causes even older protons to also break.