At last year's WWDC, Apple announced that macOS Mojave will be the last version of macOS to run 32-bit apps. With public beta of the next major version of macOS — macOS Catalina — now here, it's no surprise then that Catalina has dropped support for 32-bit apps. While most popular apps will remain unaffected by the change, it's possible that some of your apps will no longer run under macOS Catalina.
If any of your apps has recently given a warning that it is “not optimised for your Mac and needs to be updated” when launched, it will not work when you upgrade to macOS Catalina. If you've not come across this warning but are curious to see what apps on your Mac are still 32-bit, it's pretty simple to do that.
How to find 32-bit apps on your Mac
Here's how to check what apps on your Mac are 32-bit if you are running macOS Mojave or earlier:
- Click on the Apple icon in the top-left corner of your screen.
- Click on About this Mac.
- Click on System Report…
- In the left pane, select Applications sub-head under Software.
- Click on the 64-Bit (Intel) column header — usually the rightmost column — to sort the list of apps by this value.
- All apps with No are 32-bit apps.
Note that the 64-bit (Intel) column header does not show up in the report under macOS Catalina — ostensibly because 32-bit apps are no longer valid applications and won't show up in this report at all — so you should run this check before upgrading to macOS Catalina.
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