Setting proton prefix on a different drive than where the game is

[ŊormaŋďŊadoŋ]

I tried Steam support for this one, but they won't help with Linux related questions (and that is odd since the Deck is sold by Valve, and Proton is developed by them too!)

Usecase: I have games on my SD card, or any other drive, but the game requires that the prefix be on the main drive otherwise it crashes...
I don't have enough space on the main drive for the game, but for the prefix, no problem...

I can easily make it work if I launch the game from a terminal manipulating the proton commands and prefix location, but I can't do it from Steam UI.

I tried launching the game with WINEPREFIX, STEAM_COMPAT_DATA_PATH and STEAM_COMPAT_INSTALL_PATH in the launch option without success

Q1 - How do I launch a game from a drive, using a prefix on a predetermined location that could be on another drive?

Q2 - Can the prefix location be forced globally on Steam? Like, can I say I ALWAYS want it in my home folder?

(this use case became even more pressing now that EA made their disgusting EA app launcher mandatory and it breaks as soon as it is not on the main drive, on PC or on the Deck!)

[nicoper]

Originally posted by ŊormaŋďŊadoŋ:

Q2 - Can the prefix location be forced globally on Steam? Like, can I say I ALWAYS want it in my home folder?

Have you tried using a symbolic link?

Also, I found a github issue that might be related to your problem[github.com]

[eighthgrader]

I can easily make it work if I launch the game from a terminal manipulating the proton commands and prefix location, but I can't do it from Steam UI.

I tried launching the game with WINEPREFIX, STEAM_COMPAT_DATA_PATH and STEAM_COMPAT_INSTALL_PATH in the launch option without success

The STEAM_COMPAT_DATA_PATH is the right one, as I recall, and the fact that you can successfully launch the game from CLI using it confirms that. So I would make a silly guess and suppose that when you are setting it in launch options in Steam UI you just forgot to add %command% to the end of the options string.

Also, from what I know, WINEPREFIX won't have any effect when using Proton (even though Proton is based on Wine).

[ŊormaŋďŊadoŋ]

Originally posted by retif:

I can easily make it work if I launch the game from a terminal manipulating the proton commands and prefix location, but I can't do it from Steam UI.

I tried launching the game with WINEPREFIX, STEAM_COMPAT_DATA_PATH and STEAM_COMPAT_INSTALL_PATH in the launch option without success

The STEAM_COMPAT_DATA_PATH is the right one, as I recall, and the fact that you can successfully launch the game from CLI using it confirms that. So I would make a silly guess and suppose that when you are setting it in launch options in Steam UI you just forgot to add %command% to the end of the options string.

Also, from what I know, WINEPREFIX won't have any effect when using Proton (even though Proton is based on Wine).

Thank you @retif, I tried both with and without %command%

The main issue is with EA games... the installer seams to do whatever it wants!
(I really hate this launcher, I wish Steam could one day get rid of it as it adds nothing to the game, except problems!)