MacSim Version 0.8 b3 Available

23 Oct 2025

A new update to MacSim has just been released:

The simulator is now better protected from invalid inputs and instructions attempting to access memory outside its bounds.

Invalid and unimplemented instructions can also be set to stop the simulator with an error or continue with a warning and there is now a messages panel to display warnings generated by the simulator.

This is also various interface improvements and bug fixes.

It also uses Apple’s new interface frameworks so the minimum OS version to run it is now 10.14 and requires Apple Silicon (an M-series Mac). Unfortunatly it is also unsigned which means the first time you run MacSim you will have to approve opening it by visiting the Privacy & Security panel of the System Settings.

Instructions for opening an app from an unregistered developer can be found on the Apple forum. Hopefully an upcoming version will be signed and eventually be in the app store. The basic MacSim will always be free but there may be a paid version with extra features in future.

You can download the latest version of MacSim here.