MacBook Air 
Mac computers: Sleep Indicator Light behavior
This article details various Sleep Indicator Light (SIL) behaviors and what they mean.
Try safe mode if your Mac doesn’t finish starting up
You can use safe mode to help you resolve issues that might keep your Mac from completely starting up.
Sync iBooks between your Mac and your iPhone, iPad, or iPod touch
Books you buy from the iBooks Store are available automatically on all of your Mac and iOS devices.
How to take a screenshot on your iPhone, iPad, and iPod touch
You can capture the screen on your iOS device using the Sleep/Wake and Home buttons.
MacBook Pro: Bottom case foot replacement DIY instructions
This article details the do it yourself (DIY) repair process for installing feet and plugs for MacBook (13-inch, Aluminum, Late 2008) and MacBook Pro computers that exhibit missing or damaged bottom case feet.
Adjust the intensity of haptic alerts on your Apple Watch
Your Apple Watch can tap you on the wrist when you get messages and notifications. Follow these steps to adjust the intensity of haptic alerts.
OS X: Application icon has a prohibitory sign, or "PowerPC applications are no longer supported" appears
When attempting to open a PowerPC-based application, this alert appears: “You can’t open the application (name of application) because PowerPC applications are no longer supported”. PowerPC-based applications display a white prohibitory sign over their icon in the Finder.
Mac notebooks: Spotlight indexing may make the fans run
Sometimes you may notice that your computer’s fans run on high after you perform a data migration from another computer and Spotlight begins to index your hard drive for the first time.
Use Keynote Remote on your iPhone, iPad, or iPod touch
Learn how to use Keynote Remote to control your Keynote presentation from a compatible iOS device.
Learn about overscan and underscan
You might see the terms “overscan” or “underscan” used in OS X, Apple TV, or your favorite app. This article explains what these terms mean, and how selecting or changing related settings affect output to a television.
