Read OS X Mountain Lion Pocket Guide Online
Authors: Chris Seibold
Tags: #COMPUTERS / Operating Systems / Macintosh
OS X Mountain Lion Pocket Guide (13 page)
Most Macs come with a built-in display that doesn’t
require special configuration, so display problems are uncommon. When
they do happen, they’re often caused by user error. The fix, while
usually easy, isn’t readily apparent. Here are some things to
try:
- Fuzzy/tiny display
If your display is fuzzy or everything is suddenly
bigger than you remember, it’s possible that someone changed the
display’s resolution (on some systems, this may also manifest
itself as a small screen with black bars around its edges). Head
to
→
System
Preferences
→
Displays and look
for the monitor’s native resolution (on Macs with built-in
displays, this is usually the highest resolution available—the
one at the top of the list). Once you select the optimal
resolution, things should look normal again.- Your display moves with your mouse
The weird thing is that this always happens when
children under five are on your lap while you’re using your
computer. Is there some kind of kid detector in your Mac that
causes this? Nope—your kid just pressed some keys while you were
working. (If you don’t have kids or lap cats, then it was
probably you.)There are a couple of key combinations that will
cause your Mac to zoom the screen. The most common is holding
down Control while you zoom in or out with your mouse or
trackpad. Once you’re zoomed in, your mouse will suddenly start
dragging the screen around, which is disconcerting if you aren’t
expecting it. To turn it off, hold down Control and zoom out
with your trackpad or mouse wheel.There are a couple of other key sequences that can be
invoked accidentally: Option-⌘-8 toggles keyboard zooming on and
off, and holding down = or − while pressing Option-⌘ zooms in or
out, respectively.
A misbehaving application is bad enough, but a Mac that
won’t start properly is truly disconcerting. The good news is that most
such problems are repairable. The general method of attack in this case
is to get your Mac to a state where you can run Disk Utility and repair
the drive. However, there are some situations where you can’t even get
to that point.
If your Mac just beeps at you when you try to start it
up, it’s trying to tell you something: one beep means there’s no
memory (RAM) installed, and three beeps means your RAM doesn’t pass
the integrity check. The problem could be a bad RAM module, so you’ll
need to open up your Mac and replace the module.
Try installing some memory that you’re certain is fully
functional to see if that resolves the problem. If you don’t have any
spare memory lying around, try removing all the RAM modules and then
replacing them one by one until you’ve isolated the bad module.
If you don’t know how to replace memory in your Mac, check the
user guide that came with it. Or if your Mac is still under
warranty, just take it into an Apple Store for service.
If you suspect you’ve got a physical hard drive problem,
you need to check things out quickly before they get much, much worse.
If you hear a strange noise coming from your machine, that’s an
obvious sign of a hard drive problem, but these issues can also be
indicated by the computer stalling for several seconds at a time (or
making a clicking sound when stalling).
Just as with a car, when a bad sound is emanating from your hard
drive, it’s usually a bad thing. If you’ve ever listened to National
Public Radio’s
Car Talk
, you know that one of the
highlights is when callers try to imitate the sounds their cars are
making. If you’re inclined to try identifying your hard drive’s sound
by ear, head over to
http://datacent.com/hard_drive_sounds.php
and take a
listen to the sounds of dying drives, sorted by manufacturer.
If your hard drive is failing, you’re likely to lose
more data every moment it’s running. If you don’t have current
backups, your best bet is to replace the drive immediately and
either seek a data-recovery professional or, if you don’t have the
money for that, install the damaged drive in an external drive
enclosure and use the GNU ddrescue utility (
www.gnu.org/software/ddrescue
)
to recover the data on the damaged drive.
If you aren’t hearing any unusual sounds but still
suspect your hard drive is causing your problems, head to Disk Utility
(Applications
→
Utilities
→
Disk Utility) and check the S.M.A.R.T. status
of the drive. (Using a computer means loving acronyms, and this time
the acronym is clever, if a little forced: S.M.A.R.T. stands for
Self-Monitoring Analysis and Reporting Technology.)
S.M.A.R.T. isn’t available on every drive, so if you don’t see
this option, don’t worry!
The idea behind S.M.A.R.T. is that many hard disk failures are
predictable and computer users, if given a heads-up that their hard
drive is on the verge of failing, will be able to recover data
before
the failure actually happens. You can find
your drive’s S.M.A.R.T. status by opening Disk Utility and selecting
the disk you’re worried about in the list on the left. In the
lower-right part of the Disk Utility window, you’ll see the S.M.A.R.T.
Status (
Figure 4-3
):
either Verified (everything is fine) or “About to Fail.” If you get
the “About to Fail” notice, don’t waste any time: if your Mac is under
warranty, take it into an Apple Store; otherwise, back up your data as
soon as possible and start pricing out a new drive.
Figure 4-3. “Verified” means this drive is fine
S.M.A.R.T. isn’t perfect (that’s no surprise—nothing is). You
can have a problematic drive that S.M.A.R.T. won’t recognize. So if
you’re having consistent problems and S.M.A.R.T. keeps telling you
everything is fine, don’t discount the drive as the source of the
problems after you’ve exhausted other fixes.
Thankfully, the hardware failures just described are
relatively rare. Much more common are software failures: corrupt
files, wonky login items, and even font problems can cause a startup
failure. These issues are generally repairable, hopefully without data
loss. Unfortunately, when you have one of these problems, the cause
isn’t immediately obvious. When faced with a Mac that won’t boot,
there are a few things you can try to get your computer back to a
usable state:
- Restart your Mac
A lot happens when OS X starts up: it checks your
Mac’s hardware, prepares the system software, and more. During
the startup process, there are ample opportunities for something
to go wrong, especially right after you install an update to OS
X or even an application. If your Mac won’t complete the startup
sequence, don’t panic; simply restart the machine by holding
down the power button until you hear a chime; chances are
everything will be fine.WarningIf you see a flashing question mark when you try
to start your Mac, it means that your machine can’t find its
startup disk. In that case, skip ahead to “Restart in Recovery
Mode” later in this list.- Safe Boot
If a simple restart doesn’t do the trick, it means
you have problems that persist across restarts, so the next step
is a Safe Boot. In Safe Mode, all your Mac’s startup items are
disabled, font caches are cleared, and some other potentially
problematic items are avoided. More important, Safe Boot gives
you a chance to run Disk Utility, uninstall any software that
may be misbehaving, or back up your data before whatever is
causing the problem gets worse. To boot your Mac in Safe Mode,
restart it while holding the Shift key. Once you see a progress
bar appear on the lower half of the screen, you can release the
Shift key and your Mac will boot in Safe Mode. Once it has
booted, run Disk Utility (Applications
→
Utilities
→
Disk Utility).NoteWhen you’re booting in Safe Mode, the Login window
automatically appears even if you usually use Automatic Login.
Don’t be alarmed by the change—it’s a sign that Safe Mode is
working as expected.- Restart in Recovery Mode
Before Lion, one remedy to try when your Mac went
bad was to boot from the DVD you either got with your Mac or
purchased when you upgraded to Snow Leopard. But since you don’t
use any physical media—DVD or otherwise—when you install
Mountain Lion, this trick doesn’t work anymore. Fortunately,
Apple realizes that, when problems occur, you might need to boot
your Mac from a different source than usual, so Mountain Lion
includes Recovery Mode.NoteYou need to be connected to the Internet to use Recovery
Mode to reinstall Mountain Lion. The Reinstall Mountain Lion
option will download every byte of the Mountain Lion
installer, so you might want to try other fixes before going
through that process.Recovery Mode lets you boot from a virtual partition
called Recovery 10.8. When you boot into Recovery Mode, you’ll
find yourself running a special system that lets you restore
your Mac from a Time Machine backup, reinstall Mountain Lion,
use Safari to look for solutions to your problem online, or run
Disk Utility. (Don’t be afraid to launch Safari even if you’re
not connected to the Internet; there’s a static web page with
basic instructions that automatically opens when you launch the
program.)NoteYou can only run one application at a time in Recovery
Mode, so if you’re running Disk Utility, say, you can’t also
launch Safari. Being aware of this limitation can save you
some frustration and endless restarts.In addition to Recovery Mode’s obvious choices, you can
also run Firmware Password Utility, Network Utility, and
Terminal by visiting the Utilities drop-down menu at the top of
the screen. With all of these options, you’ll likely find one
that can fix your Mac woes.To boot in Recovery Mode, hold down the Option key while
starting your Mac (this process should be familiar if you’ve
booted Macs from alternative disks before). You’ll be presented
with a screen that shows all the viable startup partitions
available. Double-click Recovery-10.8, and you’ll be well on
your way to diagnosing (and hopefully fixing) whatever problem
is currently plaguing your Mac.
If you have a brand-new Mac (one that came with
Mountain Lion installed), you have one more trick you can use:
Internet Recovery. If something terrible happens to your machine (a
massive hard drive failure, say) or you want to install Mountain
Lion onto a completely blank hard drive, hold down the Option key
while starting your Mac, and then choose Internet Recovery. Once you
tell your computer which network to use, it will boot from Apple’s
servers. Once booted, your Mac will download the Recovery 10.8 image
from Apple. After that, the process is the same as for a standard
Mountain Lion reinstall.
This section emphasized tools that come with Mountain
Lion because, well, if you’ve installed Mountain Lion, you have access
to them. But these tools aren’t the only ones available when things go
wrong. There are several disk repair programs (many of which are more
powerful than Disk Utility) from third parties, such as DiskWarrior
(
www.alsoft.com/DiskWarrior
)
and TechTool Pro (
www.micromat.com
).
This maneuver gets its own section only because it’s one
of the oldest troubleshooting techniques in Mac history.
PRAM (parameter random access memory) is where your Mac
stores many of its hardware settings. Resetting the PRAM almost never
resolves a startup issue, but it’s something Apple support usually
asks you to do when troubleshooting a problem (and it does, in some
rare cases, help). To reset the PRAM, turn on your Mac,
immediately
press and hold Option-⌘-P-R, and
continue to hold those keys until your Mac restarts and you hear the
startup chime a total of three times. After you do this, you may have
to reconfigure some of the system settings (like date, time, and
possibly keyboard/mouse settings if you’ve customized them).
