SteamRT3 Beta does not start

[TheJanzap]

Valve just released the Linux SteamRT3 Beta, which can be activated in the Steam settings of the beta client. But after doing so, the Flatpak does not start anymore.

> flatpak run com.valvesoftware.Steam
INFO:root:https://github.com/flathub/com.valvesoftware.Steam/wiki
INFO:root:Will set XDG dirs prefix to /home/me/.var/app/com.valvesoftware.Steam
DEBUG:root:Checking input devices permissions
WARNING:root:Missing permissions for input devices
INFO:root:Overriding TZ to Europe/Berlin

After this, the Flatpak exits.

journalctl also doesn't give much info

steam[2063]: [2026-03-21 00:27:05] Background update loop checking for update. . .
steam[2063]: [2026-03-21 00:27:05] Searching for available updates …
steam[2063]: [2026-03-21 00:27:05] Downloading manifest: https://client-update.akamai.steamstatic.com/steam_client_publicbeta_ubuntu12

Version info

> flatpak --version
Flatpak 1.16.3
> flatpak info com.valvesoftware.Steam

Steam - Launcher for the Steam software distribution service

          ID: com.valvesoftware.Steam
         Ref: app/com.valvesoftware.Steam/x86_64/stable
        Arch: x86_64
      Branch: stable
     Version: 1.0.0.84
     License: LicenseRef-proprietary
      Origin: flathub
  Collection: org.flathub.Stable
Installation: system
   Installed: 60.0?MB
     Runtime: org.freedesktop.Platform/x86_64/25.08
         Sdk: org.freedesktop.Sdk/x86_64/25.08

      Commit: 2ba439dcb2dfc2db0ecbd80a97b5a3cb1cfaa8a172dfcad59e0d9e6cd40c867b
      Parent: ac7e5fde7bf413de33cf972f274b16df591d2d44a9bb64e724bd2fb0aa6b2570
     Subject: steam_wrapper: Don't build in isolation (fbd0220e56e7)
        Date: 2026-01-21 11:01:35 +0000

[MithicSpirit]

As a workaround, I got it to start once by pressing Ctrl-C (presumably any way of sending SIGINT would've worked). I'm not sure whether that made it go back to the default runtime or if it actually worked, but I could at least revert the setting without needing to dig around inside configs.

[MaybeGITs]

Currently, the distributable does not support SteamRT3. I know it seems pretty obvious, but there are issues with the library links.

[garecrow]

Interestingly, if you run steam via terminal and then close the terminal without manually killing the flatpak, steam does in fact launch using RT3. Except it launches in a very broken state due to the broken library links mentioned above.

[TheJanzap]

I've managed to start Steam again by deleting the beta file in Steams configuration. This will launch Steam on the stable branch and all is well. However, trying to reenable the beta in the Steam settings will make it unlaunchable again, presumably because RT3 is still enabled.

# Make sure Steam is actually closed, I've seen it hang around in the background
flatpak kill com.valvesoftware.Steam
# Delete the file that marks the Steam beta
rm ~/.var/app/com.valvesoftware.Steam/data/Steam/package/beta
# Start Steam again, now in stable. You don't have to launch it through the terminal, .desktop files work too
flatpak run com.valvesoftware.Steam

[ahjolinna]

shouldn't this SteamRT3 issue be reported to valve as well? (to ValveSoftware/steam-for-linux )

[garecrow]

No, this is an issue specific to flatpak steam. The steam client launches fine using RT3 outside of flatpak