Windows 11 KB5124008 Causing Black Screen or Secure Boot Error on Your HP Laptop? How to Fix It

If your HP laptop went to a black screen, a Secure Boot error, or a repeating boot loop right after installing KB5124008, you're not dealing with failing hardware. It's the update. Here's how to get your laptop booting again and how to stop it from happening on the next update cycle.

What Is Causing the Black Screen After KB5124008?

KB5124008, the Windows 11 security update Microsoft released on September 8, 2026, changes how the boot process verifies Secure Boot certificates. On some HP laptops running older BIOS versions, this verification step fails, and the laptop either shows a black screen with a spinning cursor, throws a Secure Boot error such as 0xc0430001, or drops into a repeating "Preparing Automatic Repair" loop.

Microsoft confirmed on September 12, 2026: KB5124008 was breaking multiple features across different PC configurations. HP laptop owners make up a large share of the reports on HP's own support forum and Microsoft Q&A. The update installed on both Windows 11 24H2 (build 26100.9445) and 25H2 (build 26200.9445), so the problem isn't tied to one specific Windows version.

This is a BIOS compatibility issue, not a corrupted install. You don't need to reset your PC or reinstall Windows to fix it.

How Do You Know This Is What's Wrong With Your Laptop?

Three symptoms point to this specific bug rather than a general hardware fault. First, the timing: your laptop worked fine before a Windows update installed, and the problem started right after a restart. Second, the error itself: a black screen with only a cursor visible, a Secure Boot violation message, or a loop landing back on the HP logo instead of reaching the lock screen. Third, the model: this issue is concentrated on HP consumer and business laptops, particularly models shipped with BIOS versions from 2024 or earlier and never updated since.

If your laptop instead shows a full blue screen with a stop code, or won't power on at all even after a full charge, treat it as a separate hardware problem and start with HP's hardware diagnostics instead of the steps below.

How Do You Get Into Windows When the Screen Is Black?

If Windows won't load at all, you need to force your way into the recovery environment, then uninstall the update from there.

1. Hold the power button for 10 seconds to force the laptop off.
2. Turn it back on. As soon as you see the HP logo, hold the power button again to force it off.
3. Repeat this two or three times. Windows detects the failed boot attempts and switches to "Preparing Automatic Repair" on the next startup.
4. Wait for the blue "Automatic Repair" screen to load, then select Advanced options.
5. On the Choose an option screen, select Troubleshoot.
6. Select Advanced options, then Uninstall Updates.
7. Select Uninstall latest quality update.
8. Enter your BitLocker recovery key if prompted. Find this key at account.microsoft.com/devices/recoverykey if you didn't save it elsewhere.
9. Confirm the uninstall and let it finish, then select Continue to boot back into Windows.

This removes KB5124008 specifically and restores your previous boot configuration. It doesn't touch your files, apps, or settings.

How Do You Uninstall the Update if Windows Still Boots?

Some HP laptops don't fully black-screen. Instead, they show intermittent flicker, delayed wake from sleep, or a brief black screen before the desktop loads. If your laptop still starts up, remove the update from inside the OS instead of using recovery mode.

1. Open Settings.
2. Go to Windows Update.
3. Select Update history.
4. Scroll down and select Uninstall updates.
5. Find KB5124008 in the list and select Uninstall.
6. Restart when prompted.

This path is faster and doesn't require a BitLocker key, so use it whenever your laptop still boots.

Why Does a BIOS Update Matter Here?

The BIOS update matters because it's the actual fix, not a workaround. Uninstalling KB5124008 only stops the symptom for now. Windows Update will try to reinstall the same patch again within days, and without an updated BIOS, the Secure Boot conflict comes right back.

Once you're back in Windows, update your BIOS before you do anything else:

1. Open HP Support Assistant (search for it in the Start menu, or download it from HP's support site if it's not installed).
2. Go to the Updates tab.
3. Look for a BIOS or "System BIOS" update. If HP Support Assistant doesn't show one, go to support.hp.com, enter your laptop's exact model number, and check the BIOS section of the driver page directly.
4. Install the BIOS update and let the laptop restart on its own during the process. Don't close the lid or unplug the power during a BIOS flash.

HP has been shipping updated BIOS versions for affected models specifically to resolve Secure Boot certificate handling, so check even if your BIOS looks reasonably current. A BIOS from 2024 or early 2025 is a common trigger for this issue.

Should You Reinstall KB5124008 After the BIOS Update?

Yes, once your BIOS is updated, it's safe to let Windows Update reinstall KB5124008, or wait a few days for KB5129195 to arrive instead. KB5129195 is the out-of-band emergency update Microsoft shipped on September 14, 2026, and it resolves several other bugs from the same update cycle, including explorer.exe crashes. Microsoft hasn't listed the HP Secure Boot issue as fixed by KB5129195 specifically, so the BIOS update is still the part doing the real work for this particular problem.

If you'd rather not deal with either update landing on your laptop again unexpectedly, pause updates for a short window: go to Settings, Windows Update, and select Pause for 1 week while you confirm the BIOS update solved things.

How Do You Avoid This the Next Time HP Ships a Windows Update?

Check for a pending BIOS update every time Windows flags a major cumulative update, not only after something breaks. HP Support Assistant runs a background check on a schedule, but it doesn't always surface BIOS updates as urgently as it surfaces driver updates, so open it manually and check the Updates tab yourself once a month.

Second, keep your BitLocker recovery key somewhere reachable without your laptop, such as printed out or saved in your Microsoft account on another device. Every fix in this article assumes quick access to it. Without it, you're stuck waiting on a longer recovery process.

Third, if your laptop is on a slower update pace already (business edition, delayed feature updates, or a managed device), don't assume you're protected. KB5124008 hit both consumer and business builds, and older BIOS versions are the common thread, not the Windows edition.

What if the Fixes Above Don't Work?

If your laptop still won't boot after uninstalling the update and updating the BIOS, check your BIOS Secure Boot settings directly. Restart, press F10 repeatedly during startup to enter BIOS setup, go to the Security tab, and confirm Secure Boot is set to Enabled with the standard Microsoft certificate keys, not a custom or cleared key database. Some users found a prior BIOS reset had cleared the Secure Boot keys, a separate issue from the KB5124008 bug producing a similar-looking error.

If Secure Boot settings look correct and you're still stuck, contact HP support directly with your laptop's serial number. Several affected models are eligible for a hardware diagnostic at no cost while this issue is active.

Your laptop's data is not at risk from this bug. It's a boot configuration conflict, not a drive failure or corruption issue, so don't jump to reformatting or reinstalling Windows from scratch.