Download Mortar

Free and open source. The latest release for Windows and Linux, on x64 and ARM64.

Windows

Windows 10 and 11. Mortar installs for your user, so it needs no administrator rights.

Installer, x64Most PCs Installer, ARM64Snapdragon and other ARM PCs Portable, x64Runs from any folder Portable, ARM64Runs from any folder
  1. Run the installer. It puts Mortar in %LOCALAPPDATA%\Programs\Mortar and adds Start Menu and Desktop shortcuts.
  2. The builds are not code-signed yet, so SmartScreen says “Windows protected your PC” the first time. Choose More info, then Run anyway.
  3. Mortar updates itself from then on.

Scoop

From Mortar's own bucket, with every download pinned by its SHA-256. Scoop then handles updates. 

scoop bucket add mortar https://github.com/Rethunk-Tech/scoop-bucket
scoop install mortar/mortar

Linux

Install from the package repository and Mortar updates with the rest of your system. Pick your distribution:

Ubuntu and Debian

Ubuntu 24.04, Debian 13 or newer, on amd64 and arm64. 

sudo curl -fsSLo /usr/share/keyrings/mortar-archive-keyring.gpg https://mortar.rethunk.tech/packages/mortar-archive-keyring.gpg
sudo curl -fsSLo /etc/apt/sources.list.d/mortar.list https://mortar.rethunk.tech/packages/mortar.list
sudo apt update && sudo apt install mortar

Or install a single .deb without updates: sudo apt install ./mortar_*_amd64.deb

Fedora

Fedora 39 or newer, on x86_64 and aarch64. dnf asks once to import the key; check its fingerprint against the one below. 

sudo curl -fsSLo /etc/yum.repos.d/mortar.repo https://mortar.rethunk.tech/packages/mortar.repo
sudo dnf install mortar

Or install a single .rpm without updates: sudo dnf install ./mortar-*.rpm

Arch Linux

x86_64 and aarch64. These commands trust the Mortar key, add the repository to /etc/pacman.conf and install. 

curl -fsSL https://mortar.rethunk.tech/packages/mortar-archive-keyring.asc | sudo pacman-key --add -
sudo pacman-key --lsign-key 3283604606CAE2295D476F9883BC8751EE6F773D
curl -fsSL https://mortar.rethunk.tech/packages/pacman.conf | sudo tee -a /etc/pacman.conf
sudo pacman -Sy mortar

Or install a single package without updates: sudo pacman -U mortar-*.pkg.tar.zst

Flatpak

Any distribution with Flatpak, x86_64 only. It brings its own libraries, so it also runs on older systems.

Flatpak bundlex86_64 
flatpak install --user mortar-linux-x86_64.flatpak

The sandbox only sees the usual game folders. For a game installed elsewhere, run flatpak override --user --filesystem=<folder> tech.rethunk.Mortar. Install the bundle again to update.

AppImage and portable program

Ubuntu 24.04, Debian 13, Fedora 39 or a newer Linux (glibc 2.38). Both update themselves in place.

AppImage, x86_64Nothing else to install AppImage, ARM64Nothing else to install Portable, x86_64Uses the system's GTK 4 and WebKitGTK 6 Portable, ARM64Uses the system's GTK 4 and WebKitGTK 6 
chmod +x mortar-linux-x86_64.AppImage
./mortar-linux-x86_64.AppImage

The first run adds Mortar to your applications menu and takes nxm:// links and .mortar files.

Homebrew on Linux

From Mortar's own tap, pinned by SHA-256. It installs the AppImage, which needs FUSE 2 (libfuse2). Homebrew then handles updates. 

brew install rethunk-tech/tap/mortar

Packages are signed by “Mortar packages <[email protected]>”, fingerprint 3283 6046 06CA E229 5D47 6F98 83BC 8751 EE6F 773D. Repository details

Browser extension

Optional. It marks Nexus Mods pages with what your profile already has and hands Mod Manager Download clicks to Mortar. Mortar's Settings › Downloads links it too. What it does, and privacy.

FirefoxSigned by Mozilla; open the file in Firefox Chrome, Edge and other Chromium browsersLoad unpacked from the zip
  1. Chromium browsers: unzip the download, open chrome://extensions, turn on Developer mode, choose Load unpacked and pick the unzipped folder.
  2. Firefox: open the .xpi in Firefox, or drop it on about:addons. It stays installed and updates itself.

Checksums, release notes and every build: latest release on GitHub.