I have a Dell Latitude 7400 2-in-1 laptop and recently the "mute microphone" function on the f4 key has stopped working. Normally, when I press the f4 key, the white LED light indicator should toggle on and off to show whether the internal microphone has been muted or not. However, the "mute microphone" function is not working anymore and as such, the white LED light indicator is always off. I have tried uninstalling and reinstalling audio/microphone/keyboard drivers and resetting my BIOS settings already but to no avail. I would greatly appreciate any support or information on how to fix this issue.
I managed to fix the issue by going to and downloading any "urgent" driver updates such as the System BIOS as well as any keyboard or audio-related drivers.
Apparently Dell released a new Realtek Audio driver today (Jan 4, 2021, possibly while I was posting my issue) that resolved the issue after being installed. Version 10.0.66.126, A03.
Are you aware that F keys toggle between functions depending on whether the FN is pressed? Try pressing the F4 key alone without the FN key You should be able to change the default from Media keys or standard keys in keyboard settings. See this for more info-- Latitude 7400: Keyboard Function Guide | Dell US
@caseyhn- Thanks for publishing this. I also have the same issue today with my Latitude 9510 2-in-1. It was working perfectly prior to Christmas, and now no longer works. I also looked in the BIOS for maybe a setting that changed but found nothing. At this time Dell SupportAssist says there are no required driver updates, and upon checking the Dell Support Website, it seems there are no drivers or BIOS files I am missing, so it seems that SupportAssist and the Dell support website are in sync, but my problem still exists.
On Jan 1, Dell SupportAssist did find two driver updates and installed them for me:
1) Intel AX210 /... Bluetooth UWD Driver - A12 and 2) Intel AX210/... WiFi UWD Driver - A14.
so I did a System Restore to a point prior and this did not fix the issue. I see there was one more driver update on Dec 11 (Intel Dynamic Tuning Driver - A07) and performed a system restore to remove this version, and it also did not fix the problem.
There were also quite a few windows updates during this time, but I am assuming that this feature (Microphone Mute on F4) would be a Dell Hardware / BIOS related thing and not controlled by Windows.
Is it possible for you to point to one of the potential drivers or was it a BIOS install you believe solved your issue - I'm guessing you did a BIOS update?
Hi there, I seem to be having the exact same problem on the same hardware. However I was unable to find where these new drivers are. Could you please clarify how you got the system to check for updates? It seems a critical part of your answer has been removed.
Brad L (retired)
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Posted March 11th, 2022 11:00
If drivers/updates do not resolve this, here is a video that might help:
(edited)
Brad L (retired)