Don’t update your Mac to macOS Catalina without doing some serious checking first. The new Mac operating system makes some deep changes, which means that at least a handful of apps on your Mac will break. And that’s probably the best-case scenario. If you’re a long-time Mac user, this could be a chaotic update for you.
So, how do you know which apps are going to break in Catalina? Here are two ways to check.
No 32-bit Mac apps allowed
The biggest change in Catalina is that 32-bit apps will no longer run. This has been coming for a while. Way back in High Sierra, Apple started warning us that certain apps were no longer compatible and would stop working in future. That future arrived with the macOS Catalina update. You can read all about 32-bit apps in this Apple support document.
To quickly check which of your Mac’s apps are still 32-bit, open up the Mac’s System Profiler. Just mouse up to the Apple menu item and choose About This Mac. Then, when that app opens, click on System Report…. If you hold down the ⌥ key when you initially mouse over the Apple Menu, About This Mac will change to System Information…, and you can click that to go straight there.
Read more at CultOfMac.com