MacOS 10.14 Mojave, the version of the Mac operating system before macOS Catalina, is the last version to support 32-bit software. With Catalina, only 64-bit software is supported. (The current version of macOS is Monterey 12.x, with macOS Ventura 13 in the fall.)
If you’re using a Mac with Mojave and can upgrade it to a more recent operating system, you’ll need to do a little more than usual to prepare your Mac. You need to make sure that your apps are 64-bit versions. If your app is a 32-bit version, it won’t work. Also, some older Macs don’t work on more recent versions of macOS; for example, you may be able to upgrade from Mojave to Catalina, but you may not be able to upgrade further.
Apple started warning people about the change with macOS 10.13 High Sierra. When you launch a 32-bit app in High Sierra, you’ll see a warning that your app needs to be updated. The warning only appears once in High Sierra and in Mojave it appears every 30 days.
If you can’t remember whether an app needs to be upgraded or not, there are a couple of ways to find out in addition to the launch warning. Here’s how.
Use Go64 to find 32-bit apps on your Mac
St. Claire Software has a great app called Go64 (free, donations accepted) that scans the software on your Mac and tells you if each app is 64-bit or not. Go64 is fast and also provides web links to the app developer’s website so you can see if the developer has an update. Read more about Go64.
Find 32-bit apps on your Mac through System Report
1. In the Finder, click the Apple menu and select About This Mac.
2. In the Overview section, click the System Report knob.
3. In the left column of the system report, scroll down to the Software section. Then select Applications.
4. The section on the right can be left blank for a moment. This is because your Mac is compiling a list of software on your Mac. When the window appears, it has two sections. The top section is the list of software. The lower part shows more details about an item when you click on it in the list.
If you click and hold the dot in the dividing line between the two sections, you can resize the window so you can see more of the list or more details.
5. In the list is a column called “64-Bit (Intel)” on the far right of the top row. If you don’t see it, try expanding the window by clicking and dragging on the right border, or you can slide the window to the right. Once you see the 64-bit (Intel) column, you can click, hold, and drag it to the left to move it closer to the app names.
6. Now you can see whether a particular app on your Mac is 64-bit or not. If it’s listed as Yes, it’s 64-bit. If it’s No, it’s a 32-bit app and you’ll need to upgrade it before you can use macOS 10.15.
Find 32-bit apps on your Mac through Activity Monitor
There is an app called Activity Monitor that you can use to determine whether an app is 32-bit or 64-bit. But it only works when an app is launched and running.
1. Start Activity Monitor, that’s in Applications > Utilities.
2. In the CPU section, you will see a list of apps running on your Mac. Right click on the top row of categories. In the pop-up list that appears, select Friendly.
3. At the right end of the top row, a new column called “Kind” should appear. You can click, hold and drag it to a new location if you want. Like for example next to the application names.
4. The Kind row will tell you whether a running app is 32-bit or 64-bit.
Upgrade 32-bit apps to 64-bit
Once you’ve identified a 32-bit app, you’ll need to upgrade it or it won’t work in macOS 10.15. Upgrading usually involves downloading an update made by the developer.
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like you bought the app from Apple’s App Store, check it for updates. Click Updates in the left column of the App Store app. Available updates appear in the larger window on the right.
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Check the developer’s website for an update.
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Some apps can check for updates in the app. Launch the app and look for “Check for Updates” or something similar in the Help menu, or in the menu named after the app (for example, the Safari menu in Safari), or in the app’s preferences.
