Information Technology Reference
In-Depth Information
Tip 322
Make Use of Boot-Time Options
By holding down various key combinations before the Apple logo first appears
when booting, you can do things such as boot from a CD/DVD or switch to
your Microsoft Windows Boot Camp installation. Here's a table of key combi-
nations—you can release the key once booting is underway, and you see the
boot progress indicator (the spinning circle beneath the Apple logo). Note that
most of these shortcuts won't work if you have FileVault enabled.
Keyboard
Shortcut
Description
OPTION
Switch between operating systems installed on your computer
(that is, Mac or Windows) or access the rescue system. This also
lets you choose to boot from an attached storage device, like a
USB memory stick.
Boot into safe mode, in which your Mac starts with only strictly
necessary kernel modules loaded and no start-up programs.
SHIFT
This is ideal for repairing a damaged system that won't boot any
other way.
Boot from CD or DVD.
C
N
Network boot (usually useful only in corporate environments).
Boot in Target Disk Mode,
21
in which case the operating system
doesn't load but the computer's hard disk can be accessed from
another computer via a FireWire connection.
T
X
Force Mac OS X to boot, even if the system can't identify a Mac
OS X hard disk (useful when things break).
COMMAND
+
R
Boot to recovery mode—allows you to check the disk, restore
from a Time Machine backup, and reinstall OS X.
COMMAND
+
S
Boot to single-user mode of OS X (a command-line prompt,
useful for making repairs).
COMMAND
+
V
Boot in verbose mode, showing boot-time messages rather than
the Apple logo. This is useful for diagnosing boot problems.
Eject button
Eject any inserted CD/DVD (holding the mouse button does the
same thing).
