Audience
Anyone who uses a Mac computer
Platform
Mac ()
About the Change
Up until October 2019, the Mac operating system supported applications that were both "32-bit" and "64-bit". Starting with macOS Catalina 10.15, Apple has stated that applications which are 32-bit will no longer run on the newest macOS and beyond. For the last few versions of macOS, launching a 32-bit app would produce a one-time alert that "<App Name> is not optimized for your Mac." Apple has been supporting 64-bit applications, which can access dramatically more memory and enable faster system performance, for many years, so if you have not seen such messages on your macOS High Sierra (10.13.4) or later Mac, you are likely not using any 32-bit apps and will not be impacted by the change.
How to check your operating system version and the "bitness" of the applications that are installed
- Click the Apple icon () in the top left corner of your screen
- Click "About this Mac"
- The window that opens will show the name of your operating system (i.e. macOS Mojave), with the specific version number listed below it
- Click the System Report... button near the bottom of the window
- In the left menu under Software, click Applications (it will take a few seconds for the application list to appear)
- You can expand the size of the list by clicking the dot below the list and dragging down:
- To sort the list by 32-bit or 64-bit, click the 64-Bit (Intel) column heading at the top right of the list. Any application that shows "No" in that column is 32-bit and will no longer function correctly (or at all) under Catalina. If you recognize applications that you have acquired and installed yourself, you will need to contact the manufacturer to find out if they plan to provide/develop a 64-bit version of the application. If not, you will need to look for an alternative program that will meet your needs.