Apparently since macOS Catalina 10.15 Mac disabled support for 32-bit apps?

How can Steam games like Portal 2 be played on MacBooks that have been keeping up with macOS updates?

In my case I'd like to do this on Intel MacBooks from 2015.

  • If an Intel mac then you can run Mojave in a virtual machine.
    – mmmmmm
    Jan 1 at 22:20
  • Have two bootable systems and choose.
    – Solar Mike
    Jan 1 at 23:11
  • dual boot with a work partition running latest macOS and a game partition (or external disk) running Mojave. been doing this ever since Catalina -- the only annoyance is having to reset my workspace after all the reboots.
    – vykor
    Jan 2 at 1:15

1 Answer 1


I rolled my 2018 Mac Mini back to Mojave.

In hindsight, I wouldn't have done that (I lost a few factory-loaded apps). I would have gotten a very fast USB thumb drive and put a Mojave OS (and the games) on that. That particular drive is what I used for my gaming until I got a slightly faster USB-C drive. Apple explains how to get previous versions of macOS, here.

MacWorld has a procedure on that. You might need to use a partition on a second thumb drive to install the previous version OS X installer and then reboot to that thumb drive for the installation proper in case the 10.14 installer doesn't want to run under Monterey.


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