OS Catalina has just been released and 32-bit software will not run on it. At some point, Apple will insist that users move from OS Mojave to OS Catalina. Thank you in advance for your reply. Software & Apps. What are 32-bit and 64-bit apps, and why do they matter? Posted on October 7th, 2019 by Kirk McElhearn You may have heard recent news about Appleā€™s warning to end users that the company intends to phase-out 32-bit apps running on macOS computers in 2019, with the release of macOS Catalina. StudioLive Series III Ecosystem Learn how the PreSonus StudioLive Series III Mixers can help you build a system that is tailored to your needs today but readily expandable as your needs evolve over time.

Apple began transitioning to 64-bit hardware and software technology for Mac over a decade ago, and all modern Macs now include powerful 64-bit processors that can run advanced 64-bit apps. These apps can access dramatically more memory, enable faster system performance, and take advantage of technologies that define today's Mac experience.

Apple has been working with developers to transition their apps, and in 2018 Apple informed them that macOS Mojave would be the last version of macOS to run 32-bit apps. Starting with macOS Catalina, 32-bit apps are no longer compatible with macOS.

Answer (1 of 5): At this stage, your best option is to simply not upgrade. You may be able to run an older version of macOS using virtualisation software like VMware. So, aside from doing hack described in Max Coplan's answer, it's possible to create 32-bit segments in 64-bit processes. An excerpt from Ken's mail: Speaking of code segments, the big thing that Catalina provides that enables this all to work is the ability to create 32-bit code segments in a 64-bit process.

If you get an alert about a 32-bit app

You will see one of these alerts when attempting to open a 32-bit app:

[app name] needs to be updated.
The developer of this app needs to update it to work with this version of macOS. Contact the developer for more information.

Run 32 Bit Plugins On Catalina

Catalina 32 Bit Games Steam

[app name] is not optimized for your Mac and needs to be updated.
This app will not work with future versions of macOS and needs to be updated to improve compatibility. Contact the developer for more information.

Catalina

Catalina 32 Bit Or 64 Bit

When installing macOS, you may see a list of recently used apps that are 32-bit. You can review this list before deciding to continue installation. You may also see a prohibitory symbol over the icon of each 32-bit app in the Finder, letting you know that the app will not open.

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Catalina 32 Bit Games

Catalina 32-bit Apps

Run 32 Bit Apps On Catalina Wine

For all 32-bit apps, please contact the developer of the app to learn whether an updated version of their software is available or planned.