Installing umu-launcher

On Linux, Spool launches Windows .exe games through Proton using umu-launcher (umu-run). It’s the one runtime dependency Spool doesn’t bundle — ludusavi and rclone ship inside the app, but umu-launcher is a Python application that runs games inside Valve’s Steam Linux Runtime container, so it’s installed from your distribution instead.

Spool only needs umu-run on your PATH (or pointed at directly in Settings → Compatibility → umu-run path). On first launch umu downloads the Steam Runtime it needs into ~/.local/share/umu — this is normal and happens once.

Settings → Compatibility runs a dependency check that tells you whether umu-run was found and shows the right command for your distribution.

Using the Spool install script

The Linux install script downloads umu-launcher for you when it can’t find an existing umu-run (in /usr/bin or Heroic’s tools folder). It fetches upstream’s zipapp release — a single pure-Python file, so the same download works on x86_64 and ARM64 — into ~/.local/share/Spool/tools/umu/umu-run, where Spool looks for it. No root access is needed, so this also works on SteamOS and other read-only systems. It needs python3 3.10 or newer.

curl -fsSL https://raw.githubusercontent.com/aidankinzett/Spool/master/scripts/install-appimage.sh | bash

Re-running the script on an existing install also updates that copy of umu. To install only umu-launcher and leave your Spool install alone (for example if you installed Spool from the AUR), pass --umu-only:

curl -fsSL https://raw.githubusercontent.com/aidankinzett/Spool/master/scripts/install-appimage.sh | bash -s -- --umu-only

Pass --no-umu to skip the umu step instead. A package from your distribution, below, gets updated with the rest of the system instead.

Per-distribution install

Bazzite

Nothing to do — Bazzite ships umu-run preinstalled. If the dependency check still reports it missing, your install predates the package; update the system (ujust update / rpm-ostree upgrade) and reboot.

Arch, CachyOS, Manjaro, EndeavourOS

paru -S umu-launcher        # or: yay -S umu-launcher

It’s in the multilib repository, so sudo pacman -S umu-launcher works too once multilib is enabled.

Fedora / Nobara / RHEL

sudo dnf install umu-launcher

openSUSE

sudo zypper install umu-launcher

Debian / Ubuntu / Pop!_OS

umu-launcher isn’t in apt yet. Grab a build from the releases page, or use the home-directory build described under SteamOS below (it isn’t SteamOS-specific).

SteamOS / Steam Deck

SteamOS does not ship umu-run by default, and the usual package-manager route doesn’t apply: the system partition is read-only, pacman/AUR aren’t available, and anything written into the system image is wiped on the next SteamOS update.

The install script handles this. To build from source instead, build umu into your home directory, which is writable and survives system updates. Do this from Desktop Mode:

git clone https://github.com/Open-Wine-Components/umu-launcher
cd umu-launcher
./configure.sh --user-install
make
make install

This installs umu-run under ~/.local/bin. Make sure that directory is on your PATH:

echo $PATH | tr ':' '\n' | grep -q "$HOME/.local/bin" && echo "on PATH" || \
  echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.bash_profile

Then either restart Spool so it re-scans, or set the path explicitly in Settings → Compatibility → umu-run path to ~/.local/bin/umu-run. The dependency check should flip to found.

Verifying

Once installed, confirm umu-run is reachable:

umu-run --help

In Spool, open Settings → Compatibility and use Rescan — umu-run should show as found, with the path it resolved to.