MacFormat UK – June 2019

Mac hardware GENIUS TIPS

Could I use an

iMac as a display

for a Mac mini?

> This is known as

Target Display Mode,

which works with few

models: many from

2009 through to 2014,

but not iMacs with a

Retina 5K display, for

example. Full details

are at bit.ly/mftgtdm.

Can I charge my

MacBook Air from

a solar panel?

> You’re best doing it

from a battery that has

been charged that way.

The current Air likes a

30W supply for its 50.3

watt-hour battery. The

external battery should

give at least 70 watt-

hours, and the solar

panel at least 20W, to

work well in long periods

of direct sunlight.

Hardware

quick-fire

questions

macformat.com @macformat JUNE 2019 | MACFORMAT | 59

With your external drive connected to your

Mac, run macOS Recovery over the internet –

refer to ‘If you can’t start up from macOS

Recovery’ at bit.ly/mfrcvry. Be prepared for

the system to take a while to download.

When the Recovery system finally appears,

follow bit.ly/mfreinst to install macOS on the

external drive. On that page, follow the link

that explains when and how to erase a disk,

and pay close attention to the information

there – it’s necessary to ensure the copy of

macOS on your external drive will be bootable.

Q

My Mac’s hard drive has died. Is it

possible to run the computer from

an external drive instead?

by JOHN PETERSON

A

You can, although an external disk

may be relatively slow. Ensure you

use storage with a Thunderbolt or

USB 3 connection, not an old USB 2.0 hard

drive. Don’t use a thumb drive, even if it has

USB 3.0, as speeds are often too slow. Ensure

the drive doesn’t contain anything you need.

Q

The colour has

disappeared from

my MacBook Air’s

display, and it’s difficult to

read anything on it. How

can I restore it to normal?

by KELLI ROIG

A

The most obvious

and remediable

cause is that you

have the wrong display

profile selected. In System

Prefs’ Displays pane, click

the Color tab and tick the

‘Show profiles for this

display only’ option. If you

can’t see an appropriate

profile, you can always click

the Calibrate button and

follow the instructions to

create a new one.

Next, go to System Prefs’

Accessibility pane and select

Display on the left. The items

here should not be ticked –

‘Use grayscale’ would be an

obvious culprit here – and

the two sliders should be

set to Normal. If both panes

look correct, try resetting

the SMC (bit.ly/mfrstsmc)

and NVRAM (bit.ly/mfrstnv) ,

then check the panes again.

If none of those software

settings have changed the

colour on your display at all,

then you should suspect a

hardware problem with its

graphics card. Start your

MacBook Air up in its

diagnostics mode (bit.ly/

mfapdg) and run the regular

set of tests, which should

identify such a problem with

a code that starts with VFD.

However, graphics card

failures don’t always show in

these basic tests; if the issue

persists, book time at a

Genius Bar, which can run

more advanced tests.

Colourless MacBook Air

My startup disk doesn’t work at all

The Display Calibrator Assistant isn’t as accurate as a dedicated third-party

hardware calibrator, but should restore your display’s colour profile.

Running macOS Recovery from the

internet loads it directly into memory,

as your startup disk may be unusable.