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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4 thoughts on “How to Run OS X Programs in 32-bit Mode”

  1. Must the application be ready for running in 32-bit mode ? Or will any application work fine in 32-bit mode ?

  2. trying to run cisco vpn client in 32 bit mode but option is not available. is the only way to run it in 32 bit by restarting the OS in 32bit mode or is there some other way to run it in 32bit mode from within 64 bit mode for rest of OS (i.e. so I keep my RAM).

    (NB – I know that the built in VPN client in network settings supports Cisco but I cant get this to work for some reason – guess my work’s server doesnt like it for some reason)

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