Before you upgrade your Mac desktop or laptop to macOS Catalina, which is now available, there’s something that you should consider first: if you use 32-bit apps, they won’t work on the new macOS update. When Catalina arrives later in 2019, it will support 64-bit apps exclusively, making macOS Mojave (version 10.13) the final major version to support 32-bit apps.

Is this change guaranteed to impact you? No, especially if you mainly use Apple software. Apple wrote on a support page that it has worked to transition its own apps to 64-bit for over a decade. However, whether you rely on two apps or 200, it’s important to know which ones may be affected. Using this process, I found out that five of the hundred or so apps that I have installed will need to be updated before macOS Catalina arrives. While none of the five were important to me, the loss of a really vital app could be a deal-breaker as far as upgrading is concerned.

If you use macOS Mojave and have been using any apps that won’t be supported by the new OS, you may have seen a pop-up alert from Apple saying that the app isn’t optimized for future versions. (One will display every 30 days when you open the app.) Otherwise, you’ll have to do a little digging to see if your favorite apps make the cut. Thankfully, it’s easy to do.

How to see if your apps are 32-bit or 64-bit

I’m using a MacBook Air running macOS Sierra (version 10.12.6) to run through these steps, though the same method applies for desktops and laptops running macOS Mojave as well.

On your desktop, click the Apple logo in the top left corner of your display, then select “About this Mac” in the drop-down menu

A new window will appear that displays the top-line specs of your machine, including when it was manufactured, its processor and RAM, its serial number, and more. What you want to focus on right now is the “System Report...” button near the bottom of the window. Click it.

Doing so will open another window. The left side shows categories (Hardware, Network, Software) and subcategories (ATA, Audio, Bluetooth, Camera, etc.) of the hardware and software that make up your system. The right side shows you the data that’s pertinent to that category. Scroll down to the “Software” category, and select “Applications.”

The right-hand window may go blank for a few moments while it populates with a list of your installed apps. Once the list appears, look for the column headed “64-Bit (Intel),” which will be the fifth column from the left. Any apps that are only 32-bit friendly will have “No” in that column.

To sort the list so that all of the 32-bit apps are together, click on the “64-Bit (Intel)” header.

What if my favorite app is still 32-bit?

If any of your apps are 32-bit, they won’t work with macOS Catalina. So, you shouldn’t update just yet. Apple says that it worked with developers to get them ready for the shift, but you can still reach out directly to your app’s developer to make your point about it, too.

To find out the best way to contact the developer(s) of an app:

Open the app in question

Once it’s running, click the app’s name located next to the Apple logo near the top left of your display

In the drop-down menu, click “About [app name].” There’s a good chance that the contact information will be there. If not, try searching for the info on the app’s website.