How to Run OS X Programs in 32-bit Mode

This brief tutorial will show you how to run OS X applications in 32-bit mode, in certain versions of OS X/macOS.

Please note: This guide was initially published back in 2009 OS X/macOS has changed a lot since then. Starting in OS X version 10.14.5 (Mojave) Apple removed the “easy way” to run apps in 32-bit mode (see Update below for an alternative that works in 10.14.5). If you’re using a version of OS X earlier than 10.14.5, this guide is still 100% accurate and applies to you.

Otherwise, if you want to run 32-bit apps on your Mac you’ll need to run a version of OS X earlier than 10.14.5 as a virtual machine in VirtualBox (or other VM).


If you’re using a OS X 10.14.5 you can no longer use the “Open in 32-bit mode” featured outlined below, but you can try the following command to launch an app in 32-bit mode:

arch -i386 /Applications/

Although OS X was 64-bit compatible in many ways prior to Snow Leopard, Snow Leopard made a big jump in 64-bit computing by re-writing most system applications, including the Finder, Mail, Safari, iCal, and iChat, in 64-bit code. This allows these programs (and others as they are re-written) to use a lot more memory than was previously possible.

The drawback is that some programs (addons, plugins etc) that interact with these 64-bit programs, often don’t work (at least until they too are re-written in 64-bit).

One way to get around this ‘problem’ is to launch the application itself in 32-bit mode, so that all of it’s 32-bit plugins and addons continue to work.

To do so, select the program in question, right-click it (ctrl-click for single mouse button folks), and select Get Info

right-clicking a program in OS X

In the Info panel, select Open in 32-bit mode. Close the Info panel and launch the program. It will now be running in 32-bit mode.

Get Info panel for Safari

Don’t forget to remove that check-mark in order to run the program in its native 64-bit mode (once the plugins, addons or whatever it is that caused you to require it running in 32-bit mode are updated).

That’s it!

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