On the evening of Monday, September 23rd, a number of film and TV editors started reporting that their workstations were not rebooting successfully. The problem was initially blamed on the Media Composer software sold by Avid.
Here's our latest update to the @Avid user community from CEO @JeffJRosica and CPO Dana Ruzicka with some helpful advice for our creative tools users running @MediaComposer on Mac Pro.
More info on OS recovery
https://t.co/DsUk7qdf39https://t.co/NKt6yMHvSZ
— Avid (@Avid) September 24, 2019
On September 24th, more instances were reported and it became clear that this was not an issue restricted to Macs with Media Composer installed. After extensive checking and testing, the folks in the MacAdmins Slack were able to narrow down the issue to an update to Google’s Keystone software, which Google uses to update Google Chrome and other Google products on macOS.
The now-pulled Keystone update attempts to remove the /var symlink, which is usually protected by Apple’s System Integrity Protection (SIP) security feature.
On Macs where SIP was disabled, this protection did not apply and the Keystone update was able to remove the /var symlink. This symlink is not a directory itself, but points to another directory (/private/var) which contains software necessary for the operating system to boot and function correctly, so removing the /var symlink rendered the affected Macs unbootable.
As mentioned previously, Google has pulled the problematic Keystone update and has published instructions on how to remediate affected Macs. For more details, please see below the jump.
Note: Remediation is only needed on Macs experiencing problems resulting from this Keystone update. If your Mac is able to boot, remediation is not needed.
To remediate on Macs running OS X 10.9.x – OS X 10.10.x, where SIP is not available:
1. Boot to Recovery
2. Identify the Mac’s boot drive using the following steps:
A. Go to the Apple menu.
B. Select Startup Disk…
C. Look for the highlighted drive. This is the startup disk.
D. Note the name of the startup disk.
Note: By default, Apple sets the name of the boot drive to Macintosh HD.
3. Quit the Startup Disk application.
4. Go to the Utilities menu
5. Select Terminal.
6. Enter the following commands:
Note: If the name of your boot drive is different from Macintosh HD, the first command should be the following:
chroot "/Volumes/Different Name Goes Here"
Use the actual name of the boot drive in the command where I have Different Name Goes Here.
7. Reboot your Mac and see if it now boots successfully.
To remediate on Macs running OS X 10.11.x – macOS 10.14.x, where SIP is available:
1. Boot to Recovery
2. Identify the Mac’s boot drive using the following steps:
A. Go to the Apple menu
B. Select Startup Disk…
C. Look for the highlighted drive. This is the startup disk.
D. Note the name of the startup disk.
Note: By default, Apple sets the name of the boot drive to Macintosh HD.
3. Quit the Startup Disk application.
4. Go to the Utilities menu
5. Select Terminal.
6. Enter the following commands:
Note: If the name of your boot drive is different from Macintosh HD, the first command should be the following:
chroot "/Volumes/Different Name Goes Here"
Use the actual name of the boot drive in the command where I have Different Name Goes Here.
7. Reboot your Mac and see if it now boots successfully.
