Latitude 7400: Unable to use external Keyboard during the preboot environment

Summary: The following article provides information about an issue with an external keyboard not working in the preboot environment when connected to a Latitude 7400 through a Dell dock.

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Symptoms

The external keyboard connected through a Dell dock does not work before the computer boots?

You may find that the external keyboard does not work when connected to a Dell dock before the computer boots to the Windows operating system. For example, this can be when you need the keyboard to do things such as entering a BitLocker PIN.

Cause

Not Applicable

Resolution

Workaround

  1. Press the F2 key on the keyboard several times until the computer enters the BIOS setup.
  2. Select POST Behavior.
  3. Select Fastboot.
  4. Ensure that Thorough is selected on the right side.
  5. Click Apply and Exit.
  6. The computer reboots. Test if the issue is resolved.
Note: The Latitude 7400 laptop must be set to Fastboot > Thorough for the Thunderbolt PBT to be engaged fully. If the BIOS has the Fastboot setting on Minimal, the external keyboard through a dock does not work.
This computer is working as designed.

Affected Products

Latitude 7400
Article Properties
Article Number: 000137646
Article Type: Solution
Last Modified: 02 Oct 2025
Version:  6
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