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About macOS 10.12 "Sierra"

With the release of macOS 10.15 in October 2019 macOS 10.12 became unsupported.

macOS 10.12 is considered insecure and not suited for use in a professional context!

If your Mac still runs a macOS version below 10.15 you should upgrade to a supported version of macOS as soon as possible!

The information below is for historical reference only.

macOS 10.12 ("Sierra") became available from the Mac App Store on September 20th, 2016. Since the

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

  • Ensure that all the software you are using is compatible with it. See below for a list of known issues.
  • Verify your hard-disk or SSD before doing the install.
  • Make sure you have a recent backup, allowing you to recover your data in case of problems.

Known Issues

This is a summary of issues known so far. Please note that this list is by no means complete. Please contact the Service Desk if you encounter a problem with an application or a service.


Using Network Groups from Active Directory (egroups in CERN speak) does not work out of the box. To be able to use Network Groups from Active Directory you have to increase the timeout for replies from the server, otherwise the request will fail and the user can not log in. To increase the timeout you should run

sudo /usr/libexec/PlistBuddy -c "Set :Modules:SystemCache:Membership\ Query\ Timeout\ in\ Seconds 20" /Library/Preferences/OpenDirectory/opendirectoryd.plist

Please note that this is only needed if you want to enable network groups from AD - if you enable individual AD accounts this is not needed.

The problem syncing imported .ics calendar entries with the Exchange Server has been fixed :)


According to there is a beta3 release of the GPG Suite for macOS 10.12.


Previous versions of MacPorts are not compatible with macOS 10.12, according to MacPorts needs to be reinstalled.

  • Adding multiple exchange accounts requires prepending "CERN\" to the email-address. Without the prepended "CERN\" you will get the mesage "The account exists already".
  • We get occassional reports about stopping to fetch new messages. We don't have the impression that the frequency of this is higher than with previous versions of But at least re-creating a deleted account appears to be much faster than with previous versions of


macOS Sierra requires MATLAB version 2106b released on October 6th 2016. All previous versions (including previous versions of 2016b) had serious issues with many non-United States regions and locales.


The previous openAFS client does not work under 10.12 (you get kernel panic a each shutdown/restart), it is recommened to uninstall it before upgrading to 10.12.

A working client is announced on, please read the description carefully before installing the client.


Only relevant for supporters: When you go to ServiceNow with Safari 10, the old interface (UI11) is rendered. The only work-around is to use another browser. For more information check .


Some GSSAPI options have been dropped. Among others the GSSAPITrustDNS is not supported any more. As a result password-less logins to services that use DNS round-robin for load balancing (lxplus, svn, aiadm,..) will not work any more.

As a work-around you can save the ssh binary from 10.11 and use that with 10.12.


It is recommended to use XQuartz 2.7.10 or later (

XQuartz installs into /opt/X11 now, and creates symlinks in /usr. If you have one of the previous versions of XQuartz that did install in /usr, the symlink /usr/X11 -> /opt/X11 cannot be installed, and some X programs will not start. In that case you have to remove the directory /usr/X11 and manually create the symlink.