Your system information

• Steam client version (build number or date): 1757650573
• Distribution (e.g. Ubuntu): Debian Sid
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes
• Steam Logs:
  steam-logs.tar.gz
• GPU: NVIDIA GeForce RTX 3060 Ti
• System : Linux 6.12.37+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.37-1 (2025-07-11) x86_64 GNU/Linux

Please describe your issue in as much detail as possible:

Steam is crashing during launch. It was working but I haven’t launched it for a while (and have made updates on my system meanwhile). I have purged mys system from it (with aptitude purge) and deleted apt sourcefiles, reinstalling it cleanly with similar steps as in the Option 2 of https://linuxcapable.com/how-to-install-steam-on-debian-linux/ with steam repositories (keeping only the basic repository steam.list ).

The terminal gives the following:

$ steam
Failed to open "/etc/apt/sources.list": [Errno 2] No such file or directory: '/etc/apt/sources.list'
Unable to determine whether the expected Nvidia drivers are available.
The Steam client may have limited functionality.
/home/yann/.local/share/Steam/steam.sh: ligne 188: VERSION_ID : variable sans liaison
steam.sh[115731]: Running Steam on debian  64-bit
steam.sh[115731]: STEAM_RUNTIME is enabled automatically
setup.sh[115821]: Steam runtime environment up-to-date!
steam.sh[115731]: Log already open
steam.sh[115731]: Steam client's requirements are satisfied
CProcessEnvironmentManager is ready, 6 preallocated environment variables.
[2025-09-20 09:57:20] Startup - updater built Sep 12 2025 03:55:50
[2025-09-20 09:57:20] Startup - Steam Client launched with: '/home/yann/.local/share/Steam/ubuntu12_32/steam' '-srt-logger-opened'
09/20 09:57:20 minidumps folder is set to /tmp/dumps
09/20 09:57:20 Init: Installing breakpad exception handler for appid(steam)/version(1757650573)/tid(115892)
Looks like steam didn't shutdown cleanly, scheduling immediate update check
CProcessEnvironmentManager is ready, 6 preallocated environment variables.
[2025-09-20 09:57:20] Process started with command-line: '/home/yann/.local/share/Steam/ubuntu12_32/steam' '-child-update-ui' '-child-update-ui-socket' '8' '-srt-logger-opened'
09/20 09:57:20 minidumps folder is set to /tmp/dumps
[2025-09-20 09:57:20] Loading cached metrics from disk (/home/yann/.local/share/Steam/package/steam_client_metrics.bin)
[2025-09-20 09:57:20] Using the following download hosts for Public, Realm steamglobal
[2025-09-20 09:57:20] 1. https://client-update.fastly.steamstatic.com, /, Realm 'steamglobal', weight was 900, source = 'update_hosts_cached.vdf'
[2025-09-20 09:57:20] 2. https://client-update.akamai.steamstatic.com, /, Realm 'steamglobal', weight was 400, source = 'update_hosts_cached.vdf'
[2025-09-20 09:57:20] 3. https://client-update.steamstatic.com, /, Realm 'steamglobal', weight was 1, source = 'baked in'
[2025-09-20 09:57:20] Using update UI: console
09/20 09:57:20 Init: Installing breakpad exception handler for appid(steam)/version(0)/tid(115894)
[2025-09-20 09:57:20] Checking for update on startup
[2025-09-20 09:57:20] Create window
[2025-09-20 09:57:20] Recherche de nouvelles mises à jour...
[2025-09-20 09:57:20] Downloading manifest: https://client-update.fastly.steamstatic.com/steam_client_ubuntu12
[2025-09-20 09:57:20] Manifest download: send request
[2025-09-20 09:57:20] Set percent complete: 0
[2025-09-20 09:57:20] Set status message: Recherche de nouvelles mises à jour...
[  0%] Recherche de nouvelles mises à jour...
[2025-09-20 09:57:20] Set percent complete: -1
[2025-09-20 09:57:20] Manifest download: waiting for download to finish
[2025-09-20 09:57:20] Manifest download: finished
[2025-09-20 09:57:20] Download skipped: /steam_client_ubuntu12 version 1757650573, installed version 1757650573, existing pending version 0
[2025-09-20 09:57:20] Nothing to do
[2025-09-20 09:57:20] Vérification de l'installation…
[2025-09-20 09:57:20] Verifying all executable checksums
[2025-09-20 09:57:20] Set percent complete: -1
[2025-09-20 09:57:20] Set status message: Vérification de l'installation…
[----] Vérification de l'installation…
[2025-09-20 09:57:21] Verification complete
UpdateUI: skip show logo
[2025-09-20 09:57:21] Destroy window

Steam logging initialized: directory: /home/yann/.local/share/Steam/logs

[2025-09-20 09:57:21] ProcessNextMessage: socket disconnected
[2025-09-20 09:57:21] No more messages are expected - exiting
XRRGetOutputInfo Workaround: initialized with override: 0 real: 0xf60c86b0
XRRGetCrtcInfo Workaround: initialized with override: 0 real: 0xf60c6f80
crash_20250920095721_5.dmp[115912]: Uploading dump (out-of-process)
/tmp/dumps/crash_20250920095721_5.dmp
/home/yann/.local/share/Steam/steam.sh : ligne 928 : 115892 Erreur de segmentation     "$STEAMROOT/$STEAMEXEPATH" "$@"

Steps for reproducing this issue:

1. Launch "steam" in terminal