Maybe is the new C++ ABI. Have you tried to disable the overlay at the game?

I've tried disabling the overlay, and using a fully native runtime. Both do not work.

@prcastro , maybe but probably not related: I'm also using ArchLinux with the latest C++ ABI and everything still runs as it was (a few games fail, but the were failing prior to this change).

@Undeterminant , I'm also seeing these errors, but I don't think this is the real problem here. Do you have any other output errors displayed when you launch steam from a terminal?

If you are using a fully native runtime, don't you get any errors?

@Undeterminant , I forgot to ask: are you using an NVidia card? If so, which driver (and version) are you using?

I'll try reinstalling Steam and we'll see how that goes.

Right now: Arch Linux, and I'm using bumblebee but only for specific games, and it still doesn't work when it's not disabled. It appears to be an error with steam overlay, because Starbound is the only game to start successfully, but it doesn't show an overlay.

Bumblebee: intel/nvidia drivers ot intel/nouveau drivers?

Also, are you able to launch some of your games as standalone from a terminal? If so, which ones? What happens (error log) for those crashing?

Is your problem recent? If so, when did you notice the problem?

Bumblebee with Intel/NVIDIA drivers here. When I override the C libraries when running steam with:

LD_PRELOAD='/usr/$LIB/libstdc++.so.6 /usr/$LIB/libgcc_s.so.1 /usr/$LIB/libxcb.so.1'

Everything works right.

@undeterminant, the solution from prcastro is one proposed on the Arch Wiki. My feeling is that one of the fixes should have solved your problem.

@Oxalin: I've tried these fixes and none of them seem to work. It really depends on the game, because it appears that the steam API itself is failing (throwing a null pointer) and many games fail to recover from this.

For example, Crypt of the NecroDancer throws the specific error:

Assert( Assertion Failed: ClientAPI_Init(GlobalInstance): GetIClientUser returned NULL. ):../../common/steam/client_api.cpp:455

Installing breakpad exception handler for appid(gameoverlayui)/version(1.0)
crash_20151226133426_4.dmp[28482]: Uploading dump (out-of-process)
/tmp/dumps/crash_20151226133426_4.dmp
Assert( Fatal Assertion Failed: ClientAPI_Init() ):main.cpp:360

Snapshot shows a full stack trace for a segmentation fault. Most other games fail silently.

And this is from part of Steam's API. And, because I have no access to this code myself, I don't have any way of specifically debugging the problem. Could be a linking problem, but I'm not sure and am lead to believe that it's not a linking problem because none of these fixes worked, and even using a native runtime fails.

This was a misconfigured firewall. Error provided was very poor, but I'm going to say that this was all my fault.

I updated the Arch Wiki to make a note of this.

Thanks for letting us know. It may help others.

@Undeterminant Could you give more details about what was wrong with your firewall settings?

@Oxalin: My firewall was blocking internal networking requests, i.e. over interface lo. For some reason, this only affected Steam. This caused this error:

Assert( Assertion Failed: ClientAPI_Init(GlobalInstance): GetIClientUser returned NULL. ):../../common/steam/client_api.cpp:455

This is a trivial networking mistake that can't be helped, although it would be nice if Steam itself provided errors whenever these libraries crashed so that people like me can more easily debug errors before bringing them up to Valve. Even just "network connection failed" would give me enough of a hint to check my firewall settings.

I have the same issue on Ubuntu 24.04 when trying to open any game with Proton