Disconnect the laptop from the dock by removing the USB-C connector from your laptop.
Unplug the power cord from the dock (circular plug that usually has a blue light indicator).
Open the laptop and reboot it.
After waiting about 30 seconds , plug the power cord back into the back of the docking station.
Reconnect the laptop USB-C connector back into the dock (always do this last)
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Dell Dock troubleshooting articles
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