Mac 
iMac (Retina 5K, 27-inch, Late 2014), Mac mini (Late 2014): Black Screen when installing Windows 8
Your computer's screen might be black when you try to start up to a Windows 8 or 8.1 install disk image using the Startup Manager (holding Option key at startup).
Boot Camp: Creating an ISO image from a Windows installation DVD
When installing Windows 7 or Windows 8 using an installation DVD, you might see the message “press any key” or your Mac might restart to OS X.
iMac (Late 2013 or later): Doesn’t start up
After you press the power button on the back of your iMac (Late 2013 or later), the computer might appear to not start up.
iMac (27-inch): AMD Radeon 6970M Video Card Replacement Program
Apple has determined that some AMD Radeon HD 6970M video cards used in 27-inch iMac computers with 3.1GHz quad-core Intel Core i5 or 3.4GHz quad-core Intel Core i7 processors may fail, causing the computer’s display to appear distorted, white or … Continue reading
MacBook Air (13-inch, Mid 2013) and iMac (Late 2013): Keyboard and Trackpad may stop functioning during Windows 8 install
The keyboard and trackpad on MacBook Air (13-inch, Mid 2013) and iMac (Late 2013) computers may stop functioning at the Personalize step when installing Windows 8.
Wireless input devices: Bluetooth frequently asked questions
Most Mac computers work with wireless input devices that use Bluetooth technology. Find answers to frequently asked questions about Bluetooth.
Mac mini (Mid 2011 and later) and iMac (Late 2012): Bluetooth keyboard may not pair during Setup Assistant
When using Setup Assistant to configure your Mac mini or iMac for the first time, the Bluetooth keyboard may have difficulty pairing.
iMac (21.5-inch and 27-inch, Late 2012), MacBook Pro with Retina display: Menu bar may not appear on first login
You may notice that the menu bar does not appear the very first time you log in to a user account on your computer (or after reinstalling Mac OS X). This may occur on iMac (21.5-inch and 27-inch, Late 2012), MacBook Pro (Retina, … Continue reading
iMac (27-inch, Late 2012): Boot Camp alert with 3TB hard drive
When you start the Boot Camp Assistant on an iMac (27-inch, Late 2012) computer that has a 3TB hard drive, the following message appears. ”Boot Camp does not support installing Windows on this Mac.”
About the "Apple Hardware Test does not support this machine" message
You may see a message stating “Apple Hardware Test does not support this machine.” This is produced when you hold down the “D” key during startup and Apple Hardware Test is not found in the hard drive.
