Security Updates to MBiL Mac OS

Critical OS X updates required

What is happening

The Mac OS on Multi-Boot iMac Lab (MBiL) Service computers must be updated to resolve recent high-profile security vulnerabilities. The updates to be installed are:

These updates will be deployed using the Casper Suite from the dates below and only install between 8:00pm and 8:00am. Following the installation of these updates, a re-install of rEFInd and reboot are required and will be carried out automatically by the update policy.

If a user is logged in at the time when the reboot is due then a message will ask if the user is OK for the reboot to happen in 1 minute. The user can choose not to click OK to postpone the reboot.

How will the works affect me?

The Macs are set to boot at 2:00am on weekday mornings if they are powered off.

  • If rEFInd in your labs is set to boot to OS X automatically (the default behaviour), no action is required on your part.
  • If you have configured rEFInd to boot to Windows by default, you will need to change this to boot to OS X by default to allow the updates to install.

After the installation, rEFInd will revert to booting the Mac OS by default.


The updates will be released to the MBiL Service labs on these dates:

  • N004/5: Monday 27th October 8:00pm
  • All MBiL labs: Monday 3rd November 8:00pm

The machines will install these updates when they next check-in with the Casper server after these times, but not between 8:00am and 8:00pm.

Further information

Please contact the IT Service Desk:<>, 01509 222333.