Compatibility Report

It probably needs older API that's not exposed currently:

12137.073:0008:0009:err:steamclient:create_win_interface Don't recognize interface name: SteamUser008
...
12145.249:0008:0009:err:steamclient:create_win_interface Don't recognize interface name: SteamGameServer003

Progress made with the recent 3.16-Beta release! It's now possible to view achievements and use the server browser. However, actually connecting to a server gets the message "This Steam account is being used in another location" in the console, along with the message box below:

However, if one uses sv_lan 1 it is finally possible to launch a listen server :)

I have this problem as well.
Obsidian Conflict, Source SDK 2007.

Proton version: 3.16.7

Already tried it, no improvement (for GE:S) unfortunately.

https://lutris.net/games/obsidian-conflict/ I tried but it isn't working on Lutris yet.

Still unable to join servers due to the error above. Attaching a fresh log.
steam-9856914317583057114.log

@kisak-valve
Is this being worked on? I don't see why this would be fixed as of 4.11-6.

4.11-8

The mod now crashes when trying to connect a server.

Attaching Proton Log
steam-14770360520569520346.log

4.11-12

The mod still crashes when creating or joining a server.

Is this being worked on?

Nope

I just tried Goldeneye: Source with Proton 5.0-5 and it launches then crashes.
I watch Source SDK Base 2007 launch and then close.

It used to run fine, but now when I try any version of Proton it crashes

Just want to add that D.I.P.R.I.P. Warm Up on steam does not work on linux with the exact same symptoms posted in OP.
https://store.steampowered.com/app/17530/DIPRIP_Warm_Up/

Proton 5.0-6

Now only single player works, listen servers will now crash. On Obsidian Conflict I can set maxplayers to 1 to force a single player session and it will work that way.

It seems it gets progressively more broken.

Also I can't seem to find this issue in the GitHub searcher, I have to use Google, anyone else?

Tried both Goldeneye: Source and D.I.P.R.I.P and both still do not work. DIPRIP will launch and I can get to the menu, but anything else will crash.

Really sucks because these games ran fine in PlayOnLinux/Wine but I prefer running them in Steam. Just easier!

Downgraded to 5.13 since Experimental just makes the screen pitch black. Joining/creating MP servers doesn't work at all.

Using Gmod 11 classic

Using Ubuntu 20.04 Focal Fossa on a Dell Latitude E6430 ATG. Unable to attach logs because none were found under Source SDK Base or Gmod 11.

I tried to play the old 2012 mod version of Black Mesa which uses Source 2007 and it crashes on launch.
steam-12487904729269010650.log
Most relevent part seems to be:

29260.412:0124:0128:warn:seh:handle_syscall_fault backtrace: --- Exception 0xc0000005 at 0xec65041e: /home/andrius/.local/share/Steam/linux32/steamclient.so + 0x56641e.
29260.412:0124:0128:trace:seh:handle_syscall_fault returning to user mode ip=7a5eb89d ret=c0000005
29260.412:0124:0128:err:steamclient:steamclient_call Access violation in ISteamUserStats_STEAMUSERSTATS_INTERFACE_VERSION002_RequestCurrentStats.
29260.412:0124:0128:trace:seh:dispatch_exception code=c0000005 flags=0 addr=7BC4B288 ip=7bc4b288
29260.412:0124:0128:warn:seh:dispatch_exception EXCEPTION_ACCESS_VIOLATION exception (code=c0000005) raised

So some issue in steamclient.so.
To reproduce download the original Part 1 and Part 2 of the mod. (the 'fixed' version on moddb is actually more broken because the people 'fixing' it didn't know what they're doing)
It need to be extracted into a folder named bms in sourcemods. Folder should NOT be named blackmesa just because the zip is.

Replying to https://github.com/ValveSoftware/Proton/issues/2249#issuecomment-2132478523

Hi,
I've looked into this issue for Source SDK Base 2006 and i think i found the cause. The issue is caused by improper IPC mapping for the interface or failed porting attempt to a newer version of the interface. (or both lol) Old Source Engine games use the IClientUser::InitiateGameConnectionOld (previously IClientUser::InitiateGameConnection) interface to generate a userid ticket for authentication, and one of the issues mentioned above causes it to attempt to dereference appid + 4 inside steamclient.so which makes it segfault. Fun fact, some games like Fortress Forever have an appid that's a valid memory location so it actually lets you connect to the server. One solution to this problem could be spoofing the appid passed to the InitiateGameConnection, which is called from CSteam3Client::InitiateConnection in engine.dll. I've been able to modify engine.dll for SDK 06, specifically replace the instruction pushing the steam appid to the esi register with a jmp instruction (to avoid issues with PE relocations) a bunch of bytes back into the int 3 block left over by MSVC (10h (16 dec) function alignment) and modify it there to something that'd be a valid memory location when dereferenced. That solution isn't really a great idea, because it only lets you join servers that are running outdated Steam binaries that don't really care about your SteamID and would let you in no matter what it is. The attached is a screenshot of GDB showcasing the attempted dereference of appid (stored in eax+ 4). If anyone's interested I could attempt to modify SDK 2007 binaries in the same way I did for SDK 2006, but keep in mind that you won't be able to stay on the server for too long if at all. If you want to play SDK 06/07 games properly on Linux you'll need to install Steam inside wine so it completely skips the lsteamclient.dll IPC proxy thing.

Edit: I didn't realize that lsteamclient was open-source until I was done writing this, so now I am able to somewhat tell what's specifically broken, and that is older InitiateGameConnection taking a uint32_t as the appid instead of a CGameID.

@caatge Not sure why you're replying to me. I'm trying to run a single-player game. No joining servers here. Game crashes on launch for me.

Sorry, my bad, it's the first time I'm using the Github comments thing.

So I decided to waste more time debugging this and got it to auth properly without any sketchy workarounds that would make VAC mad and kick you. The actual reason was the difference between the Linux steamclient function prototype and the Windows function prototype. For some reason, the Linux steamclient.so takes a CGameID* instead of a CGameID which in the end results in the Linux function being feeded 4 bytes on stack more than it needs to as well as a bad pointer. I made a small VSP (Valve Server Plugin, and yes, server plugins can be loaded on clients) which hooks the function doing the IPC call between the Unix side and the Windows side and does it correctly. More proper fix is yet to come by telling the lsteamclient C file generator thing to somehow circumvent this issue. I'm going to leave the task of actually making this correction into the C file generator to someone else, as this is my first time dealing with anything Proton and Linux related and I have no experience with the codebase and barely any idea how it works. The small plugin (which is really hacky and bases on x86 patterns) can be found here: https://github.com/caatge/proton-sdk06.

Part of the original issue reported here, creating/joining servers on Source 2007 mods, was fixed a couple of years ago, in https://github.com/ValveSoftware/Proton/commit/cd60b707564c945822a1305aef14e56b416606fa

I'm not sure about the achievements issue. There may still be a problem there, judging by ISteamUserStats crash still being reported in https://github.com/ValveSoftware/Proton/issues/2249#issuecomment-2132478523 earlier this year.

There are other reports in this thread citing the same or similar issues in Source 2006 mods. Part of that is because the server connect fix for the Source 2007 mods was only applied for the specific version of the ISteamUser interface that they target. However, the version targeted by Source 2006 mods, as well as a couple of other versions of the interface are also affected by the same issue.

I'm opening a pull request shortly to apply the same fix to the other affected versions.

A look at the ISteamUserStats issue suggests that the same underlying cause is present there. Source SDK 2006 and 2007 mods use pre-1.0 versions of the SteamWorks SDK, in which these initial two versions of the ISteamUserStats interface (001 and 002) all interface functions contain a CGameID passed by value as the first parameter. Or rather, it's by value in the header and in the Windows steamclient. In the Linux steamclient, every one of those functions that I spot-checked (around 6 of them) attempt to dereference the value, which would most likely lead to the instant crash being described.

I tested that the same fix also works for the ISteamUsersStats crash in the mod version of Black Mesa on Source SDK 2007. Updated https://github.com/ValveSoftware/Proton/pull/8375 to include that fix as well

Replying to https://github.com/ValveSoftware/Proton/issues/2249#issuecomment-2574115896

As of February 23rd 2026. Goldeneye Source servers are still not joinable with Proton Experimental with the same "Account Used Elsewhere" issue.

Replying to https://github.com/ValveSoftware/Proton/issues/2249#issuecomment-3942716533

i guess they still write malformed tickets on linux then, use https://github.com/eepycats/sdk2007-auth

i guess they still write malformed tickets on linux then, use https://github.com/eepycats/sdk2007-auth

Tried that. It doesn't help. Same error. I'm trying to play GoldenEye: Source on the Steam Deck, by the way.

does the plugin load at all? do plugin_print in console

Yes. It's loaded. I ran that command earlier and saw the full name in the console.

D:  "Auth fix plugin by @gmod9"

thats the wrong plugin, the one i linked should say "sdk2007 auth hook"
though you should run both of them if they havent fixed the other issue either but i guess try just the new one first

Yay. Ship it with the game. It works.