Your system information

• Steam client version (build number or date):
  Steam Beta Branch: Stable Client
  Steam Version: 1751405894
  Steam Client Build Date: Sat, Jun 28 3:07 AM UTC -08:00
  Steam Web Build Date: Tue, Jul 1 11:19 PM UTC -08:00
  Steam API Version: SteamClient022
• Distribution (e.g. Ubuntu):

Linux fw-home-pc 6.15.4-arch2-1 #1 SMP PREEMPT_DYNAMIC Fri, 27 Jun 2025 16:35:07 +0000 x86_64 GNU/Linux

DISTRIB_ID="EndeavourOS"
DISTRIB_DESCRIPTION="EndeavourOS Linux"
ID="endeavouros"
ID_LIKE="arch"
BUILD_ID="2025.03.19"
---
XDG_CURRENT_DESKTOP=KDE
XDG_SESSION_TYPE=wayland

• Opted into Steam client beta?: [Yes/No] No
• Have you checked for system updates?: [Yes/No] Yes

Here's a clean log where I tried to launch Infinifactory and then exit steam.

• Steam Logs: [generate by running this command in a terminal tar -zcvf ~/Desktop/steam-logs.tar.gz ~/.steam/steam/logs]

the 'Player.log'

> cat -An ~/.config/unity3d/Player.log 
     1  Player is already running$
     2   $
     3  (Filename:  Line: 452)$
     4  $

• GPU: Nvidia/Intel/AMD : Nvidia 4070

I have found out there an issue with a specific unity version related to how unity tried to enforce a single instance

game starts and exits with no errors within a few seconds ~/.config/unity3d/Player.log Player is already running

it also seems like steam is trying to run through protonm but the files are ELF executables (seems like a bug too)

/home/fw/.steam/steam/logs/console_log.txt:61:[2025-07-03 00:51:24] /bin/sh\0-c\0/home/fw/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- /home/fw/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=300570 -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime'/scout-on-soldier-entry-point-v2 --  '/home/fw/.local/share/Steam/steamapps/common/Infinifactory/infinifactory.x86_64'\0

/home/fw/.steam/steam/logs/console_log.txt:62:[2025-07-03 00:51:24] Game process added : AppID 300570 "/home/fw/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- /home/fw/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=300570 -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime'/scout-on-soldier-entry-point-v2 --  '/home/fw/.local/share/Steam/steamapps/common/Infinifactory/infinifactory.x86_64'", ProcID 32244, IP 0.0.0.0:0

/home/fw/.steam/steam/logs/console_log.txt:65:[2025-07-03 00:51:26] Game process removed: AppID 300570 "/home/fw/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- /home/fw/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=300570 -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime'/scout-on-soldier-entry-point-v2 --  '/home/fw/.local/share/Steam/steamapps/common/Infinifactory/infinifactory.x86_64'", ProcID 32244 

/home/fw/.steam/steam/logs/gameprocess_log.txt:5:[2025-07-03 00:51:24] AppID 300570 adding PID 32244 as a tracked process "/home/fw/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- /home/fw/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=300570 -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/fw/.local/share/Steam/steamapps/common/SteamLinuxRuntime'/scout-on-soldier-entry-point-v2 --  '/home/fw/.local/share/Steam/steamapps/common/Infinifactory/infinifactory.x86_64'"

Steps for reproducing this issue:

1. launch any game built with affected unity version (ex: Infinifactory)
2. game running shows up, but no game window or even a black screen, nothing
3. after a short delay it goes back to 'Play game'm wihout any error in the logs or any warning in the interface