Laptop - After Bitlocker entry buzzing from speakers and Window sloads but system then freezes at Windows logon screen and have to do pinhole\power reset to power off to try again

Question

Laptop - After Bitlocker entry buzzing from speakers and Window sloads but system then freezes at Windows logon screen and have to do pinhole\power reset to power off to try again

Graham Duffy 105

We have some laptops (mainly Lenovo X1 Yoga Gen6) that worked fine for the last 3 years or so but in last few months have started (some of them ~ 10- 15 %) to develop an intermittent issue, whereby on power on and after BitLocker PIN entry (we have that in place), the speakers emit a buzzing sound and then Windows 11 loads but the system freezes at the logon screen and the user cannot type to logon. The user then has to turn ove rthe laptop and use the pinhole\power reset to pwer the device off. Then on next attempted renoot it may load fine, or it may take 3 or 4 such events before the power on and loadup is back to normal. We have up to date Audio, graphic and Intel chipset drivers and up to date BIOS on the systems. I have tried disabling Audio smart sound and Intel Management Engine in Device Manager - still issue occurs , I have tried disabling WTD (Windows Threat Detection) by sc config wtd start=disabled at a cmd prompt - again still issues occurs. Any suggestions as to cause and possible resolution ? Think not just applicable to Lenovo laptops.

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2 answers

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Answer 1

Graham Duffy 105

Issue occurs mainly on cold boot from what users have told us but some users have the ossue on cold boot , do pwer rest and then it can occurs again on several attempted warm boots before it stops and users can logon.

Users devices get updates monthly Microsoft and Lenovo - We are currently on Windows 11 25H2 - not all devices affacted though

Fast startup is disabled by default on all devices

Issue is not BitLocker related

All drivers up to date - Audio, Graphics, Intel Smart Sound, Intel Management Engine, BIOS

Think as you say "the issue may be related to a driver initialization deadlock during early user-session startup" - but how do we find out what driver and how to resolve. I have looked at NTBTLOG.TXT when the issue occurs the lockup occurs after wtd.sys loads and I have tried via sc config wtd start=disabled to see if that was the cause but lockups till occurs when that is disabled. I will take another look at Event Logs, but if system lockup occurs before logon (i.e. by the time the logon prompt appears the system has locked up), would there be evidence in the Event Log as to what is the cause ?

Emma1-N 10,135 Reputation points Microsoft External Staff Moderator

2026-08-08T06:43:57.1933333+00:00

Hello Graham Duffy,

Thank you for the detailed update. Event Viewer may record service or driver errors before the freeze, but a complete system lockup can prevent Windows from writing the actual cause.

However, since this issue affects multiple organization-managed laptops, it is outside the scope of the Windows consumer forum. The current “Windows for home” tag is also incorrect.

Please repost under “Windows for business | Windows Client for IT Pros” or open a support case through your organization’s Microsoft support channel so the required boot-trace or memory-dump diagnostics can be reviewed.

Answer 2

Welcome Graham Duffy,

I understand how frustrating it can be when some Windows 11 devices intermittently freeze at the sign-in screen after BitLocker PIN entry, accompanied by a buzzing audio sound, requiring a hardware reset before the system will boot normally.

Before proceeding, could you please clarify:

Does the issue occur only after a cold boot, or can it also occur after a restart?
Have you noticed whether the affected devices recently received a Windows feature update, cumulative update, or firmware update before the issue started?

In the meantime, you can try these workaround steps below to troubleshoot the issue:

Option 1: Check for Kernel-Boot, Kernel-Power, and Winlogon events

Open Event Viewer
Review Windows Logs > System around the time of the freeze
Look for Event IDs related to boot, power, TPM, BitLocker, or device initialization failures

Option 2: Disable Fast Startup

Open Control Panel > Power Options > Choose what the power buttons do
Select Change settings that are currently unavailable
Clear Turn on fast startup
Restart and test

Option 3: Perform a clean boot

Press Windows key + R> type msconfig
On the Services tab, select Hide all Microsoft services and choose Disable all
Disable startup items from Task Manager
Test whether the freeze still occurs

Option 4: Update or roll back Intel-related platform drivers

Focus on Intel Dynamic Tuning, Intel Serial IO, Intel Management Engine, and Intel Smart Sound Technology drivers
If the issue began recently, test an earlier OEM-approved version from Lenovo

Based on the symptoms (audio buzzing immediately before the lockup, freeze occurring during transition from BitLocker unlock to the Windows sign-in screen, and affecting multiple devices), the issue may be related to a driver initialization deadlock during early user-session startup rather than BitLocker itself. Graphics, audio, Intel Smart Sound Technology, Modern Standby components, or a recent Windows update would be key areas to investigate.

I hope the steps above help you deal with your issue.

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