MacAuthority Corporate Solutions

This is the fourth and final post in a short series about what you can do with key combinations during startup. But this won’t be a just long list of every key combination available, we’ll also cover why and how to use them. See the the other articles to learn about Option Booting, Safe Booting, and Mouse Button Booting.

But First, a Word About UNIX

You may have seen Apple touting the fact that Mac OS X is Built on UNIX. While for most Mac Users, this doesn’t enter into the practical realm, you won’t understand Verbose Mode without knowing a little bit about the UNIX foundation of Mac OS X.

The things you usually see when booting or using your Mac, like the grey screen, Apple Logo, and later your Dock and the applications you use, are just the graphical layer of the software. Behind the scenes, your Mac is issuing and following commands, outputting results, and recording events. This occurs at a level below that of the graphical layer and results in a lot of technical information output as text, usually saved in Log Files.

Verbose Mode

Starting up in Verbose Mode exposes detailed information about what your Mac is doing during the startup and shutdown routines. Instead of displaying the grey screen and Apple Logo you are used to seeing during boot, your Mac will output the results of each step of startup as text on your screen until it reaches either automatic login or the Login Window.

When to use Verbose Mode

Verbose Mode, like most startup key combos, is most useful when troubleshooting. If your Mac is failing to boot normally, you can use Verbose Mode to track down the exact point of failure.

How to use Verbose Mode

One of the challenges of Verbose Mode is that if you don’t know what a normal verbose boot should look like, you are not going to recognize an abnormal one. So only booting to Verbose Mode when you’re having problems won’t get you far. To help you out with that, here are the top 3 words and phrases you don’t want to see in Verbose Mode when your Mac fails to boot any farther.

• panic or backtrace

  These indicate that your Mac is kernel panicking during boot. If your Mac gets to this point and no further you may want to try a Safe Boot or Option Boot to another startup drive and see how far you can get.

• Still waiting for root device

  This indicates that your Mac is having trouble reading from your startup drive. A Safe Boot may correct directory problems that are preventing data access, you may need to reinstall Mac OS X, or you may have a failing hard drive.

• hanging here

  This often indicates a software issue. A Safe Boot or reinstall of Mac OS X may get you past this point.

Or, Know Your Verbose Boot

This is only recommended for the very intrepid and experienced Admins. Since the best way to recognize and abnormal verbose boot is to know a normal one, you can set your Mac to startup in Verbose Mode every time. The output of a verbose boot will vary based on Mac model and configuration, so this is only a first step is getting to know a verbose boot.

Needless to say, we only recommend doing this is you understand it, and we take no responsibility for things you do with your computer. Your admin account must be a sudoer to accomplish this. If you don’t know what this means, this is not for you.

1. Open Terminal
2. Run the following command
3. sudo nvram boot-args=”-v”
4. Exit Terminal and Restart

That’s it for our Startup Key Combo series. We didn’t cover the list exhaustively, or even each option exhaustively; that’s too deep a topic to cover here, but this is enough to get you started.

Josh Oakes, Corporate Sales & Apple Authorized Technician