“Starting with the release of Mac OS X 10.4.6, Apple began unifying the PowerPC and Intel releases of Mac OS X. This required a specific low-level library in Mac OS X to be updated in such a way that nothing else, not even the system itself, could be using the library during the update process,” Thomas Brand reports for Egg Freckles. “Thus a second restart was required.”
“People who had shutdown their computers after the first restart were confused when their Macs failed to boot the next time they were turned on, and instead restarted a second time,” Brand reports. “Even worse was the fact the second restart often took several minutes to complete, causing impatient users to hold down the power button on their machines potentially corrupting Mac OS X.”
Brand reports, “The reason Apple is automatically unlocking FileVault 2 in Mavericks is to avoid the potential confusion a second restart would cause on today’s even larger and less prepared Macintosh user community.”
Read more in the full article here.