I bought the game when my SteamDeck arrived around June. It was playable but after a few weeks it stopped launching. I tried to troubleshoot it by verifying the installation and some other attempts before that and somehow it worked again, but a few weeks later it stopped working again and now I'm stuck because no advice I can find seems to work. I don't really want to download the entire game again or unnecessarily want to reset my SteamDeck
Out of frustration with poor search results I write this answer here. Your next best stop is ProtonDB, but it is a stream of disorganized comments. Most other tips are written from a PC consumer only point of view dealing with updating drivers and disabling security software. Reasons I quit Windows as my primary private OS over a decade ago, to escape from most of the time consuming chores and irrationality.
FH5 does not start, but after downloading the entire game again it starts
I've waited for a few weeks and for updates of different components in the chain (Forza Horizon itself, SteamOS, Proton, Wine, Proton's and Wine's GE versions) which did not make it start again since I installed it around June this year. I tried changing to different compatibility tool versions several times, and deleting proton files several times. I tried it from the SteamDeck user interface and from the desktop, several times.
What now worked in my situation was to download the entire game again (+120GB with DLC!) and it suddenly worked as intended. It's pretty wasteful from my point of view, but I had no idea where it could have been stuck. Now I have an idea. It asks you to sign in to your Microsoft account, and as I learned before this happens trough a browser. I have no idea how the code works to be honest! But in the situation of downloading a huge amount of data again or fixing some tiny little setting to fix that login step which must be happening every time the game starts I would do that, despite that some may call this kind of tinkering borderline hacking/cracking/cheating. I bought the game for good money in a place where it said that it would at least start and be somewhat playable.
From my point of view I see a code smell pattern here: assume that some functionality always completes successfully, omit error handling and provide no feedback to the user.
My observation about Firefox on SteamDeck acting as winebrowser--what it usually does on most other Linuxes--in some confusing ways correlates with my attempts to make Doom64 run properly and thus installing Firefox from flatpak, which was not installed before and somehow changes a behavior of winebrowser on my SteamDeck. Currently the Firefox icon in my KDE taskbar is replaced with the blank mime type icon and it reads winebrowser.
Sorry I'm typing my fingers wound here about theory I have no scientific proof of right now, but I wanted to put it somewhere.
Resetting your SteamDeck
Don't do it!
It's a waste of time and shows how little people know about systems who suggest that you do that. Rebooting is okay, that returns the system to a known good state. Moving some of your users configuration files out of the way and to a backup should do the trick when you are desperate and you don't throw away valuable data for scientific analysis if you ever need to do that (which one should!).
A lot of solutions for games to run properly on the Steam Deck is to have them run through Proton Experimental. This works for Red Dead Redemption 2, God Of War, Forza Horizon 5, and any other high powered games.
To obtain Proton Experimental do the following:
- Start your Steam Deck in Desktop Mode
- Find Proton Experimental
- Go into the Beta and hit "Bleeding Edge"
- Download it
- Return to Gaming Mode
- Find the game you want to run (e.g. Forza)
- Go into Settings -> Compatibility
- Force Proton Experimental
The game should run correctly now.