Find a Macintosh Computer's Operating System Version


Use these steps to determine a Macintosh computer's operating system (OS) version.  This information may be needed if you are reporting an issue or registering your computer for use at CUIMC.

Apple refers to versions of the Macintosh operating system by number as well as a name. For example, Mac OS 10.15 is also called "Catalina". On your Mac computer you can look up the OS version number.

  1. Click the Apple icon in the upper left corner of your computer screen.
  2. From the drop-down menu that appears, select About This Mac. About This Mac link in Apple menu
  3. The About This Mac window will appear. Look under the Apple logo and macOS heading for the specific Version number.
    In the picture below the Mac is using OS 11.6, which is OS version 11 (also called Big Sur) that has received additional OS updates since 11's initial release indicated by the .6.
    NOTE: Some versions such as Mac OS 10.15 may have an additional number indicating other updates, i.e. 10.15.7 About this Mac Overview tab with OS version 11.6 highlighted
  4. Click the red button in the upper left of the window to close.