Don't-Miss Operating System Stories

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Installing OS X: What to do when ‘this copy of the install OS X application cannot be verified’

If you encounter an error when trying to install a fresh operating system, it could be a problem with the date and time.

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How to create a bootable macOS Sierra installer drive

Instructions for making an external drive that you can use to install macOS Sierra.

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Starting up from NetBoot and NetRestore images

Step-by-step instructions on how to use the NetInstall service.

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How to fix missing media items in the sidebar

A reader lacks Photos, iTunes, and Movies items in the Open dialog.

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How to run apps that are not from the App Store in macOS Sierra

Apple made a major change to the Security & Privacy settings that affects new software you want to run.

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How to create NetBoot and NetInstall images

The latest in our series on using the NetInstall service.

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How to fix a long pause with a black startup screen in OS X

A reader has a 45-second pause when he restarts his Mac. During that meditative period, he wonders: why?

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How to use the Tabs feature in macOS Sierra

Tabs will help clean up your windows and make it easier to find what you need.

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How to use Picture in Picture in macOS Sierra

Watch video while you're working on your Mac.

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How to use Feedback Assistant to report bugs in the betas of macOS Sierra and iOS 10

Using the public betas? Do your duty and report bugs to Apple.

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How to hand off your Mac for repair without worrying about insecure data on an SSD

A reader would prefer to not send his computer off to get fixed with all of the contents of its drive being accessible to a technician. What to do?

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How to create your first NetInstall Image

Before you can turn the NetInstall service on you need to create a network disk image to boot from. Here's how to do it.

The power of OS X’s menu bar

It’s always there and it’s often overlooked, but the menu bar is a very useful part of the Mac operating system.

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How to sort files and folders in the Finder

A reader is having folders jump about, and wants to set them in place.

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How to avoid a blank second display when using full-screen mode in an OS X app

A reader's El Capitan installation started blacking out one monitor when he's using apps full screen.