Valheim macOS

Background

A Steam leak in 2021 seemed to indicate that Iron Gate, developers of Valheim, were exploring macOS support.

Unfortunately, that seems to be in limbo currently, as pointed out by moderator Munin:

A little update: They [Iron Gate] still want do the Mac version. The question is just when. Currently, they focus on developing the Windows & Linux versions of the game (surprise, surprise - I know), and simply don't have time to work on supporting another OS.

There's already a Valheim Mac Depot (last updated in April 2021), and it runs OK ("Okay") with Unity.

After reading an article on porting Unity games to different platforms, I started experimenting with building a custom Valheim build for macOS based on the Linux version: collecting the game data, fetching the correct dependencies and stitching it all together.

Happy to report that it actually paid off 🥳

valheim-macos-footage.mp4

^{The footage above has Bloom and SSAO enabled for aesthetics; turn these off for increased performance.}

Performance

The build performs surprisingly well, given that Apple deprecated OpenGL four years ago (!).

In addition, running the game on Apple Silicon hardware requires using the Rosetta 2 translation layer, which may incur an additional performance penalty.

Some statistics thanks to the kind community members of r/macgaming:

Hardware	Resolution	Settings	FPS
M1 Max 14"	1440p	Medium	50-60fps
M1 Max 14"	1080p	Medium / High	60fps
M1 Pro 16"	1440p	Low	60fps+
M1 Pro 16"	1080p	Low	100fps
M1 Pro 14"	1440p	Medium	45-60fps
Intel 15" (2017)	800p	Low	30-40fps

Here is to hoping that Iron Gate support macOS natively in the future with Apple Silicon and Metal support. 🍻

Disclaimer

The build has been tested in both single / multiplayer and seems to function adequately without any negative effects.

That said, there is an inherent risk to using custom game builds. In particular, Valheim interfaces with Steam, Azure PlayFab cross-play services, and most likely Iron Gate's own services. These services could start treating this custom build as problematic (or the build itself may behave incorrectly) and put your account, characters etc. in jeopardy.

Warning Usage of this build script and the resulting macOS build is at your own risk. Official support channels will not be able to help you with any issues.

Building

Prerequisites

A Steam account that owns Valheim.
~15GB free hard disk space. The majority of this space can be reclaimed once the build is complete.
An internet connection to download the game data and dependencies.
Dotnet CLI
- Easiest to install via Homebrew: brew install dotnet@7.
- Alternatively, install using the official Dotnet installer.

Initial build

These steps take between 15 to 30 minutes to complete, depending on network speed and computing power.

Clone this repository: git clone https://github.com/timkurvers/valheim-macos.
Navigate to the cloned repository in your terminal of choice.
Run ./build.sh and follow the instructions.

Note The script requires Steam credentials so that Valheim data can be acquired. As the original macOS Steam client does not have access to Valheim, this is done via DepotDownloader.
Once the build script finishes, verify the presence of Valheim.app in the build folder.
If you are in dire need of disk space: the contents of the vendor folder can be safely deleted at this point. Those files are there to make future rebuilds faster, but are not necessary for the app to function once built.

Running

Start Steam and log into an account that owns Valheim.
Launch Valheim.app from the build folder.

Patching

Future Valheim patches will require updates to the build script and you may not be able to play with an outdated build. Look at the top of this README to see what version of Valheim is currently supported.

Note It may take a day or two before the script is updated to support a recently released patch.

To generate a new build:

Fetch the latest build script using git pull.
Optional: make a backup of the previous build by copying Valheim.app elsewhere.
Run ./build.sh once more.

Known issues

Steam overlay is non-functional when launched directly from Valheim.app.
- Press F2 in-game to show Valheim's built-in FPS and network details panel.
- Alternatively: add Valheim.app as a non-Steam game and launch via Steam.
Generating and entering worlds may seem to infinitely hang before a loading screen is shown. Be patient.
Steam Cloud integration may misbehave: characters or worlds not syncing across devices.

If you suspect sync trouble, check ~/Library/Application Support/Steam/logs/cloud_log.txt first.

Notable paths for troubleshooting:
- Local data: ~/Library/Application Support/unity.IronGate.Valheim-macOS-Custom/
- Remote data: ~/Library/Application Support/Steam/userdata/<steam id>/892970/remote/
The data you have stored in Steam Cloud for Valheim can be browsed online (requires login).
Game pads / controllers may not work.

FAQ

Why is there no downloadable build?

To avoid distributing copyrighted game data, the build script is provided as a means for players who own Valheim on Steam to create their own macOS build and play on their preferred hardware.

Additionally, pre-built binaries from untrusted sources could cause havoc if malicious. Having an open-source build-script available for vetting by anyone limits that risk.

How to pass launch arguments?

As the game cannot be launched directly from macOS Steam, launch it manually with the desired arguments:

open build/Valheim.app --args -console

Why is the bundle named `unity.IronGate.Valheim-macOS-Custom` internally?

This is to avoid any collisions with a potential future macOS version by the official development team.

Where does the Valheim app icon come from?

The icon is the profile image of the official Valheim Twitter account and is property of Iron Gate.

Contributions

Feedback, issues, or pull requests with improvements are more than welcome! 🙏

flindeberg/valheim-macos