Lenovo ThinkPad USB-C Dock User Manual page 20

2. I cannot play back videos on the external monitor but can play them back on the computer
monitor.
Some computers do not support the Certified Output Protection Protocol (COPP), and you will not be
able to play back the protected videos on the external monitor connected to the dock.
To play back videos on the external monitor, you can connect the external monitor to the VGA or DP
connector on your computer, and extend the display to the external monitor. For more information about
configuring the display settings, see Chapter 4 "Working with the dock" on page 9.
3. The images on the external monitor flutter.
Check the display resolution setting of the computer and ensure that the resolution is supported by
the dock.
4. The images on the external monitor are not in correct colors.
Check the color quality of the external monitor and adjust the color to the correct color. See "Setting the
color quality of the external monitor" on page 12.
5. The computer can play back Web flashes. However, when I drag the window to the external
monitor and maximize the playback window, the playback stops.
To solve the problem, update your Adobe Flash Player to the latest version.
6. The external monitor display is blank, or the images on the external monitor flutter.
Connect one or two external monitors at a time. It is not recommended that you connect three external
monitors.
Audio
I cannot hear anything through my computer speakers or I cannot use the audio connectors on the
computer.
By default, ThinkPad and other Lenovo computers use the headset and microphone combo connector on
the dock and disable built-in audio connectors when the dock is connected.
To enable the built-in audio connectors on your computer, do the following:
1. Right-click the Volume icon in the Windows notification area.
2. Select Sounds, and the Sound window is displayed.
3. Click the Playback tab to select a built-in audio device, and then click the Recording tab to select
another built-in audio device.
See "Manually enabling the headset and microphone combo connector" on page 11 for more information.
Notes:
• To apply the new settings, restart the applications that are using the audio devices.
• The settings you have adjusted will be saved until you change the settings next time.
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ThinkPad USB-C Dock User Guide