How do I set up a laptop docking station so it just works?

A dock is one cable doing four jobs at once: charging the laptop, driving one or more monitors, carrying data to drives and peripherals, and often carrying network traffic too. They all share a single connection with a fixed capacity, which is why docks fail in ways that look like monitor faults, battery faults and network faults rather than like dock faults.

What you'll need

• A laptop with a USB-C or Thunderbolt port that supports video output
• A dock with a power supply rated for the laptop
• A cable rated for video and for the laptop's charging power
• Monitor cables to suit the dock's outputs

Step by step

1. Confirm the laptop's port can output video before buying.Not every USB-C port does, even where the plug fits. Look for a small display symbol or a lightning symbol beside the port, or check the manufacturer's specification. On many laptops only one or two of the ports carry video.
2. Match the dock's power output to the laptop.The laptop's own charger states a wattage. A dock rated below it will charge slowly, or fail to keep up while the machine is working hard, and the battery will fall during use. That looks like a battery fault and is not.
3. Use the dock's own power supply, always.A dock without external power draws from the laptop instead of feeding it, which is the opposite of what you want and limits what it can drive. If the dock came with a brick, it needs the brick.
4. Use a proper cable, and prefer the one supplied.This is the single most common cause of a dock that powers the laptop but drives no picture. A USB-C cable from a phone or a battery pack is often charge-only. Where the dock is Thunderbolt, the cable has to be a Thunderbolt cable.
5. Connect the monitors and check the dock's stated limits.Docks state how many displays they support and at what resolution and refresh rate. Two high-resolution screens use most of a single connection's capacity, so a dock may support one at full quality and two at reduced quality.
6. Arrange the displays in the settings to match the desk.In the display settings, drag the screen rectangles so they sit as the physical monitors do, and set which is the main one. Otherwise the mouse leaves one screen on the wrong side, which is the most-complained-about part of any multi-screen setup.
7. Set scaling and refresh rate for each screen separately.Mixing a high-resolution laptop screen with an ordinary external monitor means each needs its own scaling to make text the same physical size. Also check the refresh rate is not sitting at the lowest option the dock will allow.
8. Update the dock's firmware.Docks are small computers and their firmware fixes real problems — displays not waking, ethernet dropping, devices disappearing. It is a step nobody expects to need and it resolves a surprising share of odd behaviour.
9. Test the undock and redock cycle.Unplug, use the laptop alone for a minute, plug it back in. Windows and applications moving to the wrong screen, or screens not waking, is the behaviour to shake out now rather than at the start of a working day.

Tips

• Wire the dock's ethernet socket to the router if you can. It is faster and steadier than wifi, and it means the laptop switches to a wired connection simply by being docked.
• Keep the dock out from behind the monitor stand where you can reach the ports. A dock you have to grope for defeats the point of it.
• If the laptop runs hot while docked, remember it is charging, driving screens and often being used with the lid shut. Give it air, and see the guidance on airflow before assuming a fault.

Common mistakes

• Buying a dock without checking the laptop's port supports video — No dock can add a capability the port does not have. This is the one thing to establish before spending anything.
• Using whatever USB-C cable was to hand — It is the leading cause of the black-monitor symptom. A cable that charges perfectly may carry no video at all, and there is no way to tell by looking.

If it doesn't work

Questions people ask