In case those of you still using Yosemite might have missed or overlooked it, Apple released a security update this morning (January 17, 2017) which also fixes a kernel issue that sometimes makes the system to become unresponsive. The update is available through the App Store and the installation requires a restart.
"All you've got to do is own up to your ignorance honestly, and you'll find people who are eager to fill your head with information" --Walt Disney
