I am actually having this very same issue, even after following the appropriate steps towards the NTFS External Hard Drive that the games are on, along with having the proton installs on the local drives instead of the external drive. This external drive is also used with the windows edition of Steam as well, as I run a dual-boot setup between Windows 10 version 2004 (Release Preview) and Ubuntu 20.04 LTS, with all Packages up to date running off of Proton 5.0

One note to this is that this issue is solely within Proton, using regular wine to launch the exe's in those folders work, while Proton's show as Running for a few moments then stops. I have also confirmed that the drive is also readable and writable since native Linux games are able to work on it, and the aforementioned fact of normal wine working on it.

Here is the Steam log for one such game, which is Ultimate Custom Night
steam-871720.log

System Info: https://gist.github.com/CDAGaming/11405a919ef287365455bda59c303c47

@kisak-valve

@kisak-valve That actually turned out to be the issue, The symlink part is the portion I had neglected to do, due to the warning that I could lose data, and me not wanting to initially take that risk. Though after biting the bullet on that one and doing the link, it is indeed properly launching games with proton.

Thanks for your quick assistance!

I have the same issue, but I think the issue is not really, or only partially with Proton. For me it is simply every game which I have to use Proton for. But I am able to use Proton with the respective Proton prefix manually from command line just fine. To me it seems, that the Steam client itself is broken and cannot properly make the call with Proton prefix and executable file of a game.

For a little more detail check my other post: https://github.com/ValveSoftware/Proton/issues/2141#issuecomment-622611566 (At the time of that post, I did not realize, that the problem is the same for all Proton requiring games, that I have.

Of course this has consequences for netplay, which is not available for any game I run without Steam knowing it, using the Proton prefix manually.

Also having this crash. Reproduces on multiple games. The following appears in the dmesg:

[13001.876043] python3[41617]: segfault at 0 ip 0000000000000000 sp 00007ffde58a34c8 error 14 in bash[400000+18000]
[13001.876046] Code: Bad RIP value.
[13001.956789] python3[41620]: segfault at 0 ip 0000000000000000 sp 00007fff148ea7b8 error 14 in bash[400000+18000]
[13001.956791] Code: Bad RIP value.
[13002.018101] python3[41623]: segfault at 0 ip 0000000000000000 sp 00007ffd838bd8f8 error 14 in bash[400000+18000]
[13002.018103] Code: Bad RIP value.
[13002.145667] python3[41627]: segfault at 0 ip 0000000000000000 sp 00007fffcb9ebc88 error 14 in bash[400000+18000]
[13002.145673] Code: Bad RIP value.
[13002.358647] python3[41637]: segfault at 0 ip 0000000000000000 sp 00007ffcb21ed048 error 14 in bash[400000+18000]
[13002.358649] Code: Bad RIP value.

(Ubuntu 20.04).

Cracked it - for me, steam was invoking python3 from nix, and not from the system.

Conceptually, this is my setup:

1. Install nix, run exec bash -l to get nix in your $PATH
2. Run nix-env -i python38.
3. which python3 reports /home/pwaller/.nix-profile/bin/python3 which is a symlink to /nix/store/w1zn1h8px8jkm18z4f3qndif1mvrdhxw-python3-3.8.2-env/bin/python3.

Steam works fine in this environment, but launching proton games does not (they silently exit immediately). If I remove /home/pwaller/.nix-profile/bin from my $PATH, then everything works again.

Then Steam should package its own Python version including dependencies it needs to work properly.

Unfortunately in my case I am not running Steam in any environment. Just plain Ubuntu 18.04. No idea what Python Steam is using or whether it uses any Python at all. If it uses a wrong Python, then Steam is buggy.