The Harmony package, used by Udon Sharp, and a handful of third-party community plugins for runtime patching in the editor, has been updated to officially support ARM64 on all platforms (Windows, Linux, and yes, Mac). This will correct any in-editor issues when running the Unity Editor on these platforms. Whilst VRChat itself may only support PC & Android, the Unity Editor is a cross-platform utility, and there are a variety of folks with ARM-equipped machines who use such hardware for primary development, and therefor experience issues with the editor without patching. With the advent of full iOS support on the horizon, this may further increase the # of Mac-based content creators. Please update the provided package. Release notes for version where ARM64 support was added Addendum An experimental VPM package can be found here which installs a debug release of Harmony 2.4.1. Unity appears to, in initial testing, prefer the package's copy of Harmony over VRChat's included version. It may also be installed using the following repo: https://misutaaasriel.github.io/Dreemurrs-Repository/index.json Note The release builds currently output a mangled DLL that Unity Burst is incompatible with. However, building Harmony against the DebugFat target using the Microsoft .NET Reference Assemblies with a .NET 4.5.2 framework target creates a successful drop in replacement. A bug report is open on this here For further reference, the original copy of Harmony is built against .NET 4.5.0, which is no longer a valid target. 4.5.2 was chosen as its nearest replacement.