- There are a few options, including reverting back to an OS that supports SimCity. You could also create a bootable external drive, install a virtual machine running a previous OS, boot camp your Mac to run the game on Windows, or consider purchasing a copy from the App Store. The post above yours has a link to the stickied thread with more information about this. If you're considering any of the options for running a previous version, I highly suggest reading the details and how-to blog here: https://bluebellflora.com/running-32-bit-apps-after-macos-mojave/
High Sierra 10.13 crashed SimCity, so if you revert to HS, install a previous version
Mojave 10.14.4 has an issue with handling high def and ultra high def resolutions, so you will need to force the resolution in Origin under SimCity's Advanced Game Options, or install a previous version
Aspyr has updated their single player version of SimCity to 64 bit, so you could purchase from the app store.