Mac 
iPhoto for iOS: Downloading videos from Journal pages
Videos in journals published to iCloud from iPhoto for iOS 1.0.1 or later can be downloaded when viewed on a computer.
iPhoto for iOS: Can’t publish to iCloud
When you try to publish to iCloud, you may see the message “Unable to publish to iCloud. Learn more.”
iWork for iCloud beta: Supported operating systems and browsers
Using an operating system and browser that are supported for use with iWork for iCloud beta will provide the best overall user experience.
How iTunes Store purchases are billed
Learn how your iTunes Store, Mac App Store, App Store, and iBooks Store purchases are billed to your iTunes Store account (Apple ID).
If you see a "This movie requires QuickTime" message in iTunes 12.1 or later
Although media content you buy or rent from the iTunes Store doesn’t need QuickTime to play, you might have older media files on your computer that do need QuickTime.
AirPort: Unable to join a Wi-Fi network with hidden SSID (Wi-Fi network name)
You may not be able to join a hidden Wi-Fi network even though you are using the correct password.
AirPort Express: Difficulty joining third-party network that is using WEP
Joining the network of some third-party Wi-Fi routers may require additional steps if the network is protected by WEP – Wired Equivalent Privacy (an older wireless security protocol).
AirPort base stations: How to find the Wi-Fi network when it doesn’t appear normally
You may not be able to locate your Wi-Fi network from your computer. The Wi-Fi network may not appear in the Mac OS X AirPort Menu Extra.
Manage the Wi-Fi connection on your Mac
You can use the Wi-Fi menu on your Mac to see the status of your wireless network connection, switch between networks, or turn Wi-Fi on or off.
