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About macOS 15 "Sequoia"

macOS 15 ("Sequoia") became available on September 16th, 2024.

With the release of Sonoma, Apple stopped delivering updates for macOS versions below 13, therefore all macOS versions below 13 are now unsupported. If your Mac still runs a macOS version below 13 you should upgrade to a supported version of macOS as soon as possible!

For an overview of new features in macOS 15 see https://www.apple.com/macos/macos-sequoia-preview/.

There are some important actions to take before you install it:

  • Take note of the information on https://support.apple.com/en-us/HT212735.
  • Ensure that all the software you are using is compatible with macOS 15. See below for a list of known issues (be aware that the list is far from complete).
  • Make sure to update all the third party software you are using BEFORE upgrading to macOS 15. Expect that many updaters of older software may NOT WORK any more under macOS 15.
  • Uninstall outdated software and all software you don't use anymore BEFORE upgrading to macOS 15. Expect that most uninstallers for outdated software may NOT WORK any more under macOS 15.
  • Verify your hard-disk or SSD before doing the install.
  • Make sure you have stored your data in CERNbox or have a recent backup, allowing you to recover your data in case of problems. We generally recommend to store all your data in CERNbox.
  • Make sure you have enough free disk space for the install image AND the installation process. The macOS 12 installer did start even if you didn't have enough free space, it will fail and stubbornly try again after a restart. You will need to re-install your OS if this happens, data loss is quite likely...

In case you migrate from a macOS version older than 12: You should also read the 'About macOS ...' articles concerning ALL intermediate versions of macOS, in particular the warnings about 32bit applications!

Note that if you still use the old (HFS+) Mac file system, the upgrade will most likely convert it to APFS, carefully read https://support.apple.com/en-us/HT208018.

Known Issues:

First release manifests occasional graphical glitches/delays in UI elements, desktop widgets, screen savers and lock screens. Some already installed applications may require you to give them more permissions manually in Settings on first open. The configuration profiles summary & installation in System Settings has been moved from Privacy & Security -> Profiles to General -> Device Management.

ESET

ESET Antivirus (6.x, 7.x) does not work with macOS 15 Sequoia. ESET Endpoint Security (8.x) works only starting from version 8.1.6.0. You must update/upgrade your antivirus to ESET Endpoint Security version at least 8.1.6.0 before upgrading your OS to macOS 15. Both fresh install and upgrade policies for that are available in the Mac Self Service.

Users having unsupported version of ESET installed on macOS 15 will see an annoying popup informing about lack of compatibility. ESET UI will be inaccessible and it will be impossible to install the update manually. In such case we recommend to uninstall ESET AV / ES through Mac Self Service.

For users having ESET AV 6.x installed, upgrading to macOS 15 can cause loosing network connectivity: ALERT8723

Parallels Desktop

Parallels Desktop 19 installer doesn't work on macOS 15 Sequoia. If you had Parallels 19 or lower installed before upgrading to macOS 15, the application will open but your existing virtual machines won't run.

Parallels Desktop 20 supports macOS, the policies to install or upgrade from older versions are available in Mac Self Service. It's recommended to update to Parallels 20 before upgrading OS to macOS 15.

Local Network Privacy

There is a new feature in macOS 15 called Local Network Privacy. Now application that wants to interact with devices on user’s local network must ask for permission the first time that it tries to browse the local network. This does not apply to launch daemons running as root. This manifests as a popup asking: Allow to find the devices on local network? The list of applications with the permission can be managed in System Settings -> Privacy & Security -> Local Network.

This popup seems to not appear for the applications run from Terminal (e.g. Python scripts) and can cause connectivity issues for them.

WiFi MAC address randomization

Similar to iOS, Apple introduced an option to hide your real MAC address when connecting to WiFi networks. When Rotate Wi-Fi Address is on for a network, the MAC address for that network will change approximately every two weeks. Addresses for forgotten networks always rotate after at most 24 hours.

This option should be disabled when accessing the CERN network (GPN), as device access is granted by its MAC address registered in LanDB.

You can find more details in KB0009897.