Find out whether your Mac’s apps are 64-bit or not (for Catalina).

macOS Catalina (10.15) is coming in the Fall of 2019. The only apps that can possibly work with Catalina take memory from the system in 64-bit chunks and are therefore termed “64-bit apps.” Apps that take memory in 32-bit chunks (“32-bit apps”) won’t work with Catalina at all– they won’t even launch. Here’s how you find out which of your apps definitely won’t work– that is, here’s how you find out which of your apps are NOT 64-bit.

Note: just because an app is 64-bit doesn’t mean it’s going to work properly with Catalina. There might still be problems and you might still need to get updates for those apps when Catalina comes along. We know for sure that 32-bit apps won’t work with Catalina, so what we are doing here is figuring out what won’t work, not figuring out what will.

Step One: download an app called “Go64” from St. Clair Software. It’s “donation-ware” (you chip in what you want to chip in). The icon looks like this:

Go64 Icon
Go64 icon

You’ll see a message:

“Apple has announced that macOS 10.14 (Mojave) will be the last version capable of running 32-bit applications. Go64 identifies the apps on your Mac that are still 32-bit so you can plan to update or replace them in the near future.”

Step Two: dismiss that message and Go64 begins scanning your Mac’s hard drive, looking for apps, and noting which are 64-bit and which aren’t. In the screenshot below you can see that my Mac has a lot of apps that are 64-bit but also a lot that aren’t.

145 of the apps on my disk won't work in Catalina.
145 of the apps on my disk won’t work in Catalina.

A quick glance at the list of 32-bit apps on my machine reveals that my copy of Parallels Desktop is a 32-bit app, so it won’t work in Catalina. Fortunately, the latest version of Parallels is 64-bit, so it’s time for me to upgrade. I’d better get on that.

Go64 includes URLs that take you to the software publishers and a column where you can manually enter the cost of the updates. Of course some of the URLs will take you to dead-ends; for example Go64 tells me that Now Up-to-Date is 32-bit, so it sends me to, but since Now Software is out of business the URL doesn’t do me any good.

Remember, Go64 is “donation-ware.” When you quit Go64 you get a list of other St. Clair products, and a “Donate” button at the bottom.

Other offerings from St. Clair Software.
Go64: donation-ware. And try the other apps!

I encourage you to donate, and to try the other apps. In particular, Default Folder X is very handy. St. Clair offers a free trial of Default Folder X, so try it!

Thanks to St. Clair Software for this useful tool.

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