GMC Sierra 2018 Owner's Manual page 196

Only USB storage devices
formatted in FAT16/32 or exFAT
file systems are recognized.
NTFS and other file systems are
not recognized.
The time it takes to process files
will depend on the USB storage
device type and capacity, and
the type of files stored.
Some USB storage device files
may not be compatible.
Up to two USB devices and one
iPod can be played through a
USB hub. All devices may not be
supported, depending on the
performance of the USB hub.
If there is not enough power
supply, it may not operate
normally.
Do not disconnect the USB
storage device while it is playing.
This may cause damage to the
product or affect the
performance of the USB device.
Disconnect the USB storage
device when the ignition is
turned off. If the ignition is turned
on while the USB device is
connected, the USB device may
be damaged or may not operate
normally.
USB storage devices can only
be connected for playing music,
viewing photo files,
or upgrading.
Do not use the USB terminal to
charge USB accessory
equipment. The heat generated
may cause performance issues
or damage.
Music files to which Digital Right
Management (DRM) is applied
cannot be played.
USB storage device that are in
capacity with a limit of 5,000
files, such as music, photo,
video, 15 stages of folder
structure. Normal usage cannot
be guaranteed for a storage
device that exceeds this limit.
The iPod/iPhone can play all
music files that are supported.
The music file lists will only
display up to 5,000 files on the
screen. These files are sorted in
alphabetical order.
Infotainment System
Some iPod/iPhone product
models may not support the
connectivity or functionality of
this product.
Only connect the iPod/iPhone
with connection cables
supported by iPod/iPhone
products. Other connection
cables cannot be used.
The iPod/iPhone may be
damaged if it is connected to the
vehicle with the ignition on.
When not in use, disconnect the
iPod/iPhone.
When the iPod/iPhone is
connected to the USB port by
using the iPod/iPhone cable, the
Bluetooth music is not
supported.
The iPod/iPhone playback
functions and the information
displayed may be different when
played on the infotainment
system.
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