protonscr

Beltomatic Failed to start: "Invalid argument: '../drive_c'"

protonclosed
ValveSoftware/Proton#9460 · opened 2026-02-03 by CalebMorris · updated 2026-02-05 · 4 comments · github
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CCalebMorris 2026-02-03 github

Compatibility Report

  • Name of the game with compatibility issues: Beltomatic
  • Steam AppID of the game: 2674590

System Information

I confirm:

  • [x] that I haven't found an existing compatibility report for this game.
  • [x] that I have checked whether there are updates for my system available.

Proton Log

steam-2674590.log

Symptoms

The game doesn't start. No windows open. Steam never leaves progresses past Launching before failing.

Reproduction

  1. Click Play from Steam
  2. Steam switches to Launching status as the game begins start process
  3. Start cancells
    a. There are no windows that pop

Personal Notes

Possible oddity that is contributing to this is that I have my steam lib on an external drive. Other games work fine though.

When running Steam from terminal to try and get any crash info that wasn't showing up on Proton log, I get the following error:

Adding process 207289 for gameID 2674590
Proton: Upgrading prefix from None to 10.1000-105 (/media/cdbitesky/WD_Black_Volume/SteamLibrary/steamapps/compatdata/2674590/)
Traceback (most recent call last):
  File "/media/cdbitesky/WD_Black_Volume/SteamLibrary/steamapps/common/Proton 10.0/proton", line 2005, in <module>
    g_session.init_session(sys.argv[1] != "runinprefix")
  File "/media/cdbitesky/WD_Black_Volume/SteamLibrary/steamapps/common/Proton 10.0/proton", line 1899, in init_session
    g_compatdata.setup_prefix()
  File "/media/cdbitesky/WD_Black_Volume/SteamLibrary/steamapps/common/Proton 10.0/proton", line 943, in setup_prefix
    os.symlink("../drive_c", self.prefix_dir + "/dosdevices/c:")
OSError: [Errno 22] Invalid argument: '../drive_c' -> '/media/cdbitesky/WD_Black_Volume/SteamLibrary/steamapps/compatdata/2674590/pfx//dosdevices/c:'
Game Recording - game stopped [gameid=2674590]
CCalebMorris 2026-02-03 github

Demo of the Steam UI behavior, in case it helps in some way

https://github.com/user-attachments/assets/447c4602-d9ce-44c3-98f2-b978c6bd69ec

CCalebMorris 2026-02-03 github

Ok, so when proto:setup_prefix is trying to create a the sym-link, it's at working path SteamLibrary/steamapps/compatdata/2674590/pfx and the drive_c is present in the /pfx/ folder, but not in the /2674590/ so it fails to create the link.

What is the intended path that it should be in that's a child of /pfx/ that it isn't actually in? Or is the /drive_c/ in the incorrect location and should be at the app-root of /2674590/?

Kkisak-valve maintainer 2026-02-03 github

Hello @CalebMorris, this is a general filesystem issue instead of a game-specific issue which is already being tracked at #5168.

The general recommendation is to use a Linux native filesystem with the Steam libraries that you use Proton with.

You might have some luck with the community written workarounds in https://github.com/ValveSoftware/Proton/wiki/Using-a-NTFS-disk-with-Linux-and-Windows, but your mileage may vary.

Closing in favor of the older issue report.

CCalebMorris 2026-02-05 github

Ah, it appears when I was testing another game to see if it was just Beltmatic, that that game had direct Linux support so it wasn't going through Proton.
Installed to an EXT4 drive, confirmed that this error is no longer showing up

Proton versions