Your system information

• Steam client version (build number or date): 1687563636
• Distribution (e.g. Ubuntu): Arch Linux
• Opted into Steam client beta?: Yes
• Have you checked for system updates? : Yes
• Steam Logs:
  steam-logs.tar.gz
• GPU: Nvidia

Please describe your issue in as much detail as possible:

I do have an issue since proton8 launch. It looks like when you have proton 8, proton experimental, proton next or proton ge 8 installed, upon launch steam tries to do some kind of check on proton enabled games and those threads hangs making steam unusable, can't launch any game. Have anyone experienced a similar issue? My workarround was to remove those version of proton and everything works as expected. I did some research without success. No log message seems related to the issue.

Here are a list of pending process after trying to close steam from interface:

$ ps -aux |grep steam
******       9073  0.0  0.0   8212  4676 pts/0    S+   08:32   0:00 bash /home/******/.local/share/Steam/steam.sh
******       9208 16.2  0.9 722608 304300 pts/0   Sl+  08:32   1:14 /home/******/.local/share/Steam/ubuntu12_32/steam
******       9220  2.7  0.0      0     0 ?        Zs   08:32   0:12 [steamwebhelper] <defunct>
******       9401  0.0  0.0   7512  3712 pts/0    S+   08:32   0:00 sh -c LD_LIBRARY_PATH="$SYSTEM_LD_LIBRARY_PATH" PATH="$SYSTEM_PATH"  STEAM_COMPAT_APP_ID='1493710' STEAM_COMPAT_TOOL_PATHS='' STEAM_COMPAT_LIBRARY_PATHS='' STEAM_COMPAT_SHADER_PATH='/jogos/SteamLibrary/steamapps/shadercache/1493710' STEAM_COMPAT_INSTALL_PATH='/jogos/SteamLibrary/steamapps/common/Proton - Experimental' STEAM_COMPAT_MOUNTS='' STEAM_COMPAT_DATA_PATH='/jogos/SteamLibrary/steamapps/compatdata/1493710' STEAM_COMPAT_CLIENT_INSTALL_PATH='/home/******/.local/share/Steam' PROTON_CRASH_REPORT_DIR='/tmp/proton_crashreports' STEAM_FOSSILIZE_DUMP_PATH='/home/******/.local/share/Steam/shader_cache_temp_dir_d3d11_64/fozpipelinesv6/steamapprun_pipeline_cache' STEAM_FOSSILIZE_DUMP_PATH_READ_ONLY='$bucketdir/steam_pipeline_cache.foz;$bucketdir/steamapp_pipeline_cache.foz' FOSSILIZE_APPLICATION_INFO_FILTER_PATH='/home/******/.local/share/Steam/fossilize_engine_filters.json' ENABLE_VK_LAYER_VALVE_steam_fossilize_1='1' FONTCONFIG_PATH='' '/home/******/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper'/_v2-entry-point --verb=run -- '/jogos/SteamLibrary/steamapps/common/Proton - Experimental'/proton run  /home/******/.local/share/Steam/ubuntu12_32/../bin/d3ddriverquery64.exe 2>/dev/null 
******       9403  0.1  0.0   4616  1664 pts/0    S+   08:32   0:00 /home/******/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper/pressure-vessel/bin/pv-bwrap --args 31 /usr/lib/pressure-vessel/from-host/bin/pressure-vessel-adverb --generate-locales --fd 21 --regenerate-ld.so-cache /run/pressure-vessel/ldso --add-ld.so-path /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu --add-ld.so-path /usr/lib/pressure-vessel/overrides/lib/i386-linux-gnu --set-ld-library-path /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/aliases:/usr/lib/pressure-vessel/overrides/lib/i386-linux-gnu/aliases --exit-with-parent --subreaper --shell=none --terminal=none -- /home/******/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper/pressure-vessel/bin/steam-runtime-launcher-interface-0 container-runtime /jogos/SteamLibrary/steamapps/common/Proton - Experimental/proton run /home/******/.local/share/Steam/ubuntu12_32/../bin/d3ddriverquery64.exe
******       9491  0.0  0.0  33256  5632 ?        Ss   08:32   0:00 /usr/lib/pressure-vessel/from-host/bin/pressure-vessel-adverb --generate-locales --fd 21 --regenerate-ld.so-cache /run/pressure-vessel/ldso --add-ld.so-path /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu --add-ld.so-path /usr/lib/pressure-vessel/overrides/lib/i386-linux-gnu --set-ld-library-path /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/aliases:/usr/lib/pressure-vessel/overrides/lib/i386-linux-gnu/aliases --exit-with-parent --subreaper --shell=none --terminal=none -- /home/******/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper/pressure-vessel/bin/steam-runtime-launcher-interface-0 container-runtime /jogos/SteamLibrary/steamapps/common/Proton - Experimental/proton run /home/******/.local/share/Steam/ubuntu12_32/../bin/d3ddriverquery64.exe
******       9515  0.0  0.2 119148 78084 ?        S    08:32   0:00 python3 /jogos/SteamLibrary/steamapps/common/Proton - Experimental/proton run /home/******/.local/share/Steam/ubuntu12_32/../bin/d3ddriverquery64.exe
******       9516  0.0  0.2 1974488 89816 ?       S    08:32   0:00 c:\windows\system32\steam.exe /home/******/.local/share/Steam/ubuntu12_32/../bin/d3ddriverquery64.exe
******       9518  0.9  0.0  16576 14672 ?        Ss   08:32   0:04 /jogos/SteamLibrary/steamapps/common/Proton - Experimental/files/bin/wineserver
******      11900  0.0  0.0   6604  2412 pts/1    S+   08:40   0:00 grep --color=auto steam

In this case I need to kill process 9516 to be able to open Steam again.

Also here is a log shown when opening steam from the terminal: https://gist.github.com/rokam/ec2dbd5d987a7ac32920966505ec7745

Steps for reproducing this issue:

1. Enable any Proton8 version (Proton8, Proton Experimental, Proton Next, Proton GE 8)
2. Try to run a game, even a game forced for Proton 7
3. Game will be forever loading, click cancel button.
4. When opening any game, the game will try to load and close. Making Steam totally unusable.
5. When closing Steam from UI, steam will remain open until kill -9 proton process.
6. No matter if you open Steam again, no games are playable

Workarround:

Delete all Proton 8 version and everything will work again.