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Getting started

This guide takes you from a fresh install to a running game in a few minutes.

Key terms

Term Meaning
Prefix A folder that holds a virtual Windows installation: its own C: drive, registry and installed programs. Each game runs inside one. Several games can share a prefix, or each can get its own.
Runner The compatibility layer that runs Windows programs. Either Proton (Valve's Wine build used by Steam, and its community variants such as Proton-GE) or a plain Wine build.
umu-launcher The tool Prefixr launches Proton through. It runs Proton inside the Steam Linux Runtime, just as Steam does, and applies game-specific fixes (protonfixes).

1. Install Prefixr

Download a package from the latest release:

  • AppImage (works on any distribution, including immutable ones like Bazzite and SteamOS):
chmod +x prefixr_*.AppImage
./prefixr_*.AppImage
  • Debian, Ubuntu, Linux Mint, Pop!_OS:
sudo apt install ./prefixr_*_amd64.deb
  • Fedora, openSUSE, Nobara:
sudo dnf install ./prefixr-*.x86_64.rpm

Start Prefixr as your normal user, not with sudo. A prefix created as root would be owned by root, and your desktop session couldn't use it afterwards, so Prefixr refuses to start as root.

2. Get a runner

Open Runners in the sidebar and click Download runner. Pick a source and a version:

Source Kind Good for
Proton-GE Proton The usual choice. It's Valve's Proton plus extra fixes and media codecs.
Proton-CachyOS Proton An alternative Proton build with CachyOS's patches.
Wine (Kron4ek) Wine Plain Wine (staging, WoW64), for games or apps that run better outside Proton.

If you're not sure, take the newest Proton-GE. Prefixr verifies each download against the checksum the release publishes.

Prefixr picks up any Proton or Wine build placed in its runners folder, so you can also copy or symlink a build there, for example from Steam's compatibilitytools.d. See Configuration & files for where that folder is.

3. Create a prefix

Open Prefixes, choose an empty folder (or type a path that doesn't exist yet) and click Add prefix. The folder is set up the first time a game starts in it.

You can also add a prefix that already exists, for example one from Lutris, Bottles, PortProton, Heroic, or a game's compatdata/<appid> folder from Steam. Prefixr uses it as it is; for Steam's compatdata folders it picks the pfx folder inside automatically.

4. Add your game

In the Library, click + Add game and fill in the General tab:

  1. Program (.exe): choose the game's executable. The name is filled in from the file name.
  2. Prefix: the prefix from step 3.
  3. Runner: the runner from step 2.

With a Proton runner, the Proton tab offers a protonfixes match. Search for your game there so umu applies the fixes known for it. Without a match, only general fixes apply.

Click Add.

5. Start it

Click the play button on the game's card (or ▶ Start in the list view). The first launch of a new prefix takes a while: Prefixr downloads umu-launcher and the Steam Linux Runtime (a few hundred MB, once) for Proton, or initializes the prefix and installs wine-mono and DXVK for Wine. The card shows Starting… in the meantime and Running once the game is up.

If it fails, the card shows the error and a Show log button. The troubleshooting guide covers the common cases.

Installing a game from its setup program

Many games come as an installer (setup.exe) rather than a ready-to-run folder:

  1. In your file manager, right-click the installer → Open With → Install Prefixr. Prefixr registers this entry the first time it starts.
  2. Choose a prefix (or create a new one with +) and a runner, then click Run setup and go through the installer as on Windows.
  3. When the installer closes, Prefixr looks for the shortcuts it created and offers them as the game to add. Pick the right one (or choose the .exe yourself) and add the game.

Optional extras

These make the matching settings work. When a tool isn't installed, Prefixr leaves its setting out at launch instead of failing the game.

Tool Enables
MangoHud The in-game overlay with FPS, frame times and temperatures
GameMode CPU governor and priority tweaks while a game runs
power-profiles-daemon Holding the Performance power profile while a game runs
Gamescope Running a game in its own compositor with a fixed resolution and FPS limit
vkBasalt Sharpening and anti-aliasing as post-processing
Steam Importing Steam prefixes and adding games to Steam
A SteamGridDB API key Cover art and other artwork

Most gaming-focused distributions (Bazzite, Nobara, CachyOS, SteamOS) ship most of these already.

Next steps