OS X: How to erase and install You can use OS X Recovery to erase your computer using Disk Utility and then reinstall OS X.
iCloud: About iCloud Security Code alert messages Learn what do to if you get an alert indicating that you entered your iCloud Security Code incorrectly too many times.
OS X: Tags help you organize your files OS X Mavericks includes Tags – a powerful new way to organize your files. Whether your files are on your Mac or in iCloud, you can find them with just one click