Mac 
Mac computers: Don’t change SD cards while computer sleeps
Don’t swap an SD card with another one of the same manufacture and capacity while your computer is sleeping. This could potentially lead to data loss.
Boot Camp: Brightness controls no longer respond after updating to Windows 8.1
After upgrading from Windows 8 to Windows 8.1 on a MacBook Pro (17-inch, Early 2011 or Late 2011), the F1 and F2 keys may no longer control the brightness of the computer’s built-in display.
Airplay mirroring freezes or drops connections on an 802.11 b/g network
When using a MacBook Pro (Late 2013) or Mac Pro (Late 2013) with Airplay mirroring on an 802.11 b or g network, the TV image might freeze or the connection gets dropped.
OS X: When your Mac doesn’t sleep or wake
Some features are designed to prevent your Mac from going to sleep. If your Mac doesn’t sleep or wake as expected, review the steps in this article.
Boot Camp: Press any key message appears while installing Windows 8 using DVD media
When installing Windows 8 on an iMac (Late 2013) or Mac Pro (Late 2013), installation may not complete if you use an optical disc for installation. Instead, you are prompted to "press any key" or the computer restarts back to … Continue reading
Using 4K displays and TVs with Mac computers
Learn about using 4K displays and Ultra HD TVs with Mac computers.
iMac (Late 2013): Understanding the first startup cycle
After you press the power button on the back of an iMac (Late 2013), the computer might appear to not start up.
Macs with Fusion drive: How to find BOOTCAMP partition in Windows installer
After running the Boot Camp Assistant, partitioning the Fusion drive, and starting up in the Windows installer, you might not be able to find the BOOTCAMP partition in the list of available partitions to install Windows on.
OS X: Identifying USB ports on your Mac
Macs that support OS X include built-in USB ports. You can use System Information or System Profiler to see how fast these ports are, and to see what’s currently connected to them.
MacBook Pro (Retina, Late 2013): Using 192 kHz sample rate digital audio
Learn how to use 192 kHz sample rate optical digital audio with your MacBook Pro (Retina, Late 2013).
