Apple fixes battery-related shutdown issue with MacBook Pro and MacBook Air firmware updates
Apple on Tuesday released a trio of SMC updates, one each for the MacBook Pro, MacBook Pro Retina and MacBook Air, that patches a minor issue some users have experienced when draining the battery down to near zero.

According to the release notes, mid-2012 MacBook Pro and Retina MacBook Pro models are affected by the update, while the MacBook Air update applied to mid-2012 and mid-2013 models.
For the MacBook Pro's SMC Firmware Update 1.8:
The latest SMC updates can be downloaded through Apple's Support Downloads webpage, or via Software Update. Those looking to grab the new firmware on Apple's website may have to wait until the respective pages are refreshed, as they currently show information and links to prior updates.

According to the release notes, mid-2012 MacBook Pro and Retina MacBook Pro models are affected by the update, while the MacBook Air update applied to mid-2012 and mid-2013 models.
For the MacBook Pro's SMC Firmware Update 1.8:
The same language is used for the MacBook Pro Retina SMC Update 1.2:This update is recommended for MacBook Pro (mid 2012) models.
This update addresses rare issues where the battery unexpectedly stops functioning or the system hangs when the battery charge reaches less than one percent.
Finally, the MacBook Air SMC Update 1.9:This update is recommended for 13-inch MacBook Pro with Retina display (late 2012) models, and 15-inch MacBook Pro with Retina display (mid 2012) models.
This update addresses rare issues where the battery unexpectedly stops functioning or the system hangs when the battery charge reaches less than one percent.
It is not clear how widespread the battery bug was, though a quick search in Apple's Support Communities webpage yields a number of hits for threads pointing to such issues.This update is recommended for MacBook Air (mid 2012 and mid 2013) models.
This update addresses rare issues where the battery unexpectedly stops functioning, the system does not recognize the battery, or the system hangs when the battery charge reaches less than one percent.
The latest SMC updates can be downloaded through Apple's Support Downloads webpage, or via Software Update. Those looking to grab the new firmware on Apple's website may have to wait until the respective pages are refreshed, as they currently show information and links to prior updates.
Comments
Macbook Pro Retina 15" here, I got this.
It's MaBook!!!!! Don't touch it!!
MaBook. Truly epic. I'm sure it's headed for the memory hole.
Downloaded on my 2012 15" rMBP. Installed. Works just as great as is always has which is flawless.
Never do a firmware update on a Mac!
Made the fans on my Mac Pro go haywire.
Made my Macbook Pro start freezing while using video apps.
Made my daughter's Macbook sound like a hair dryer.
Froze the keyboard on my clamshell iBook.
All different macs with different OSes. All happened with an updated firmware install.
Never do a firmware update on your Mac!
have anyone of you faced with issues with this smc update? (Especially studiomusic?)
I have not tried it and will not.
I'm having the SAME issue! After this SMC update on my rMBP 15, fans are spinning, battery is X'd, and magcharger led will not light. Took it into the store and they told me "bad battery". They told me that as they were testing it----WITH IT RUNNING ON BATTERY. They want $310 to fix.
This firmware hosed my machine.