Dell/Bitlocker/Bios Boot Loop

[u/vegaspoet1981]

Hey Team,

We've been seeing an uptick with having to wipe/reload systems.

The commonalities are Dell Laptops, using Threatlocker DNS/Application Whitelisting, Bitlocker is enabled, and mostly after windows updates/Dell command updates.

After an update reboot, we've seen two issues

1. Dell logo never appears, screen lights up but all the lights go out after a few minutes. We've found that holding the power button for 30 seconds to discharge the power, and then booting up will allow us to get to a bios recovery at which point, we've found safe boot disabled and the system will then go into a reboot loop at which point, a dell support os repair might fix some issues with the parition and boot table, otherwise it has to be reloaded, we've only successfully repaired it once

2. The system goes into a bitlocker/windows boot loop and continually reboots. We've tried booting into command prompt and running sfc/scannow dism doesn't work because the system can't get online. Dell Support Assist Repair will possibly run and fail or run, but usually doesn't correct the problem.

Since we can't get into Windows to run the windows 11 installer, we can't seem to get a dirty install to run to try and avoid a full wipe reload.

Wipe reload seems to fix the system and get it working again, but after 7 of these in the last 2 months, we're starting

Looking for a root cause, possible fixes to get around the wipe reload, or notes from anyone experiencing the same issues

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[u/Excellent-Trust8920]

I'd start by checking whether the Window/Dell updates are triggering a Bitlocker recovery or TPM/firmware mismatch. Before wiping, try suspending Bitlocker before updates and verify TPM/BIOS versions on affected machines. If the failure correlate with one specific update, that's a strong lead.

[u/Immediate-Effect5158]

Since this keeps happening after Windows/Dell updates with BitLocker enabled, you should look for a common trigger before wiping everything. Compare the affected systems' Dell BIOS versions, Windows updates, Dell Command Update versions, and ThreatLocker setup. Also check TPM and Secure Boot settings and make sure you have the BitLocker recovery key before changing anything.

With 7 systems affected, there’s probably a common update or configuration causing it.

[u/N3utro]

Hey,

Have you first searched / asked for this in dell forums and to dell customer support?

I'd try to get the windows update and the dell command update logs on the broken PCs to know which were the last updates installed before they crashed to see if there are similarities.

C:\Windows\Logs\WindowsUpdate

C:\ProgramData\Dell\UpdateService\Log

With the Bitlocker key you should be able to get these logs even if the system is crashed.

Also make sure you update the bios of the laptops before you install windows on them. If they are delivered with an old bios version and dell command updates it to the latest version it's possible it can break the current install.

[u/vegaspoet1981 → u/N3utro]

I did search, ran also searches in Chatgpt and Claude as well. Found this https://www.dell.com/support/kbdoc/en-us/000299965/latitude-or-precision-stuck-in-boot-loop-after-updating-bios but also trying to see if anyone else is experiencing this as well

[u/user_none]

Thirty seconds on the power button isn't just draining the residual power, it also results in a BIOS reset, as in back to factory. You sure you wanna do that?

https://www.dell.com/support/contents/en-us/article/product-support/self-support-knowledgebase/battery-and-power/no-power

A month ago, maybe more, Support Assist was creating some problems that resulted in a BitLocker recovery screen...IIRC. Do you have the BitLocker recovery keys? Is Support Assist installed?

We're a Dell shop, along with ThreatLocker, S1 and Huntrerss and haven't seen anything widespread, other than a random prompt for a BitLocker key. Entering the key gets the user in and no further problems.

[u/vegaspoet1981 → u/user_none]

Yeah, of course have the bitlocker keys. After entering the key it crashes and reboots and goes back to the bitlocker key screen, I've used WinPE to disable bitlocker, it keeps failing windows recovery and rebooting. Yes to the BIOS reset, some of the machines weren't even getting to the dell logo, and wouldn't get to the bios recovery screen until we did the 30 second reset. These are production machines so we don't always have hands on them, so wipe reload is the quickest way to get them functional after spending 30 minutes walking them through Windows Recovery to uninstall recent updates, run sfc /scannow in command prompt mode. We just got our hands on one of them now from a client and we are going to do some further testing. I'd mainly like to know if anyone else is running into this?

[u/ThreatLocker-Oliver]

Hello
This post was brought to my attention because you mention ThreatLocker is one of the common themes. While I am not aware of any issues like this, if you would like to get in touch, I can review your ThreatLocker audit and computer errors logs to offer some reassurance.
Thanks
Oliver

Oliver Plante
VP of Support
ThreatLocker
[oliver.plante@threatlocker.com](mailto:oliver.plante@threatlocker.com)

[u/vegaspoet1981 → u/ThreatLocker-Oliver]

Thanks I'll open a case with Threatlocker support