With the advent of macOS 10.15 Catalina (expected to release sometime in early fall 2019), Apple will be removing support for all 32-bit applications. Apple has been warning about this for a few years now and has gotten increasingly aggressive at informing users who run macOS 10.14 Mojave that they have dated applications that won't work in the future.

This blog entry will detail one person's efforts to clean his system of 32-bit applications (or at least become aware of the applications that will be an issue).

The easiest way to find 32-bit applications is to use Apple's System Information application, though it is not a particularly great interface. If you open About This Mac under the Apple menu and click on the System Report… button, the System Information application will launch.

We're looking for Applications information, which you can find if you scroll down to the Software section in the left-hand window. Once you click on Applications, you will likely see a substantial list including applications you forgot about or never knew existed. In my case, I started with 248 applications (I know).

You may have to expand the window to see the information we're looking for. One of the columns is only somewhat helpfully entitled 64-Bit (Intel). If the application says Yes in that column, we're okay. If it says No, we need to investigate. I sorted by that column, so every application with a No was toward the top.

The first step is to understand that installers and updaters are applications, too, so we can get rid of a bunch of them very easily. For instance, Box had 30 installers in the Application Support directory. I removed 29 of them. There were many other aged installers and updaters, many of them sitting in Application Support: I deleted an old VPN installer, an old Verizon MiFi updater, and five separate Java updates along with an Oracle finish_installation application.

Apple installers especially have companion applications: I deleted an ancient iWork Tour and a Remote Desktop Read Me. I also pulled Welcome to Leopard and Welcome to Snow Leopard.

There was other "goop" in Application Support: I removed BNProtocol Router, an old EFI utility, GoogleTalk PlugIn, GoToOpener, Microsoft Help Viewer, a Microsoft Silverlight launcher, RealPlayer Download Agent, and Roxio Restore. WebEx left a total of 21 dated applications.

For actual applications, I'll lead off with the single most significant chunk for me—old versions and components of Microsoft Office. Microsoft and Apple have worked over the years to retain compatibility for Office 2011 and Office 2008. When 10.15 comes along, that will all go by the wayside. This highlights one of the important things to remember about a transition like this one; it's not just that the application won't open—it's that the data inside can become inaccessible (or at the very least not easily accessible). In my case, there's some email in Entourage that might be needed for archival purposes. I export it to an .rge file, which newer versions of Outlook can open if necessary. The next step is to clean up the rest of Office 2008 … and … that's 22 applications removed.

I decided to wait on tackling Office 2011 and moved to older versions of FileMaker Pro. FileMaker Pro 11 and FileMaker Pro 13 were next, for a total of five applications removed (everything from 14 on is 64-bit).

Removed the old Microsoft Remote Desktop Connection application which Microsoft has replaced. Removed Adobe Content Viewer and Adobe Widget Browser. Removed Apple's Network Connect.

Known incompatibilities that will be hard to replace: dataComet-Secure 10.2.2, Fetch 5.7.7 (Fetch 5.8 currently in beta), supporting applications for Creative Cloud (not the well-known applications themselves), …