HP and Lenovo Laptops Are the Latest Victims of a Windows 11 Update

Windows updates are meant to make your computer safer, but every so often one causes more trouble than it fixes. Microsoft’s August 2026 Patch Tuesday update for Windows 11, KB5121003, is one of those. More than a month after release, owners of HP and Lenovo laptops are still reporting serious problems, from laptops that get stuck at the HP logo after restarting to Lenovo machines that keep switching to battery power while plugged in.

If your laptop started behaving strangely in the last few weeks, this guide explains what is going on, how to tell whether KB5121003 is the cause, and the safest way to fix it without losing data or making things worse.

What is Windows 11 KB5121003?

KB5121003 is Microsoft’s cumulative security update released on August 11, 2026, for Windows 11 versions 24H2 and 25H2. Alongside security fixes, it includes changes related to Secure Boot certificates and updates to some of the drivers that manage power, batteries and the ACPI system that lets Windows talk to your laptop’s hardware.

Because it is a cumulative update, its changes are also carried into later monthly updates. That is why some people who never installed it manually are still seeing the problems: Windows installs updates automatically, and a laptop left on overnight may be found stuck on a boot screen the next morning.

Since release, KB5121003 has been linked to crashing games, printer and PDF issues, and Teams and Outlook failures on Arm-based PCs. Now HP and Lenovo laptops have joined the list.

HP laptops: stuck at the logo and rolling back

Many HP owners, including users of HP OmniBook X models, report the same pattern. The update downloads and installs normally, then the problem appears at the restart needed to finish it:

1. KB5121003 downloads and prepares to install
2. Windows restarts to complete the update
3. The laptop freezes at the HP logo
4. After a forced shutdown, Windows launches Automatic Repair
5. Windows rolls the update back, and the cycle can start again

According to user reports on Microsoft’s support forums, HP support has attributed the problem to corrupted BIOS settings and recommended loading the BIOS default settings, after which the update could install or disappeared from the pending queue. Microsoft has not officially confirmed a BIOS corruption bug. An IT administrator at a managed service provider also reported similar installation failures on some Lenovo and Dell business PCs.

If your laptop is repeatedly showing “Preparing Automatic Repair”, our guide on fixing the Preparing Automatic Repair loop explains what the message means.

Lenovo laptops: losing AC power while plugged in

The Lenovo problem is different, and in some ways more confusing, because it looks like a hardware fault. Owners, mostly of Lenovo Legion gaming laptops, report that Windows briefly thinks the charger has been unplugged even though it is still connected and the charging light stays on. Typical symptoms include:

• The laptop flicking from AC power to battery and back again in a fraction of a second
• The screen dimming or going black momentarily
• A sudden drop in performance, especially during games or heavy workloads
• Kernel-Power Event ID 105 entries in Event Viewer
• The battery slowly draining while the laptop is plugged in

One Reddit user investigated by polling the laptop’s power state every 50 milliseconds. They traced the issue to battery and ACPI driver files updated around KB5121003 (including battc.sys, CmBatt.sys and acpi.sys) and found that the charger itself was not at fault. After uninstalling the update, they recorded around 15 hours without a single power drop. Some HP Victus owners have described similar behaviour. At the time of reporting, neither Lenovo nor Microsoft had publicly acknowledged the issue.

Other problems linked to KB5121003

The HP and Lenovo issues are the latest in a series of complaints about the same update. Reported problems include:

• Games crashing, which Microsoft later linked in part to RGB lighting software and provided a workaround for
• Printer and PDF problems after installing the update
• Microsoft Teams and Outlook failures on Arm-based Windows PCs

If you are having broader issues after recent patches, read our guides on PCs crashing after the latest Windows update and Windows updates slowing down your PC.

Before you try any fix

Two quick precautions can save you a great deal of stress:

1. Back up your important files

If the laptop still boots, copy important documents, photos and emails to an external drive or cloud storage before changing anything. Our guide on the best ways to back up photos before a computer repair covers simple options. If the laptop will not boot at all, stop and get help, because our data backup and recovery service can usually retrieve files safely.

2. Find your BitLocker recovery key

Many HP and Lenovo laptops have BitLocker or device encryption turned on by default. Resetting the BIOS or changing Secure Boot settings can trigger a BitLocker recovery screen, and without the 48-digit key you may be locked out of your own data. You can usually find the key by signing in to your Microsoft account on another device and viewing your recovery keys. Write it down before you continue. Learn more in our article what is BitLocker.

How to fix KB5121003 problems

Fix 1: Reset the BIOS to default settings (HP)

This is the workaround HP support has reportedly recommended for laptops stuck at the logo:

1. Hold the power button to shut the laptop down completely.
2. Press the power button, then immediately tap F10 repeatedly to open BIOS Setup (on some HP models, tap Esc first, then choose F10).
3. Load the default settings, usually with F9 or the “Restore Defaults” option.
4. Save and exit with F10, then let Windows start and retry the update.

Afterwards, check HP Support Assistant or the HP support website for any BIOS update released for your exact model. Only install BIOS updates from HP, keep the laptop plugged in, and never interrupt a BIOS update, because a failed flash can stop the laptop starting. If that has already happened, our BIOS update and recovery service can help. Not sure what the BIOS does? Read what is the BIOS.

Fix 2: Uninstall KB5121003 from Windows

Rolling back the update has fixed both the HP and Lenovo problems for many users. If Windows still starts:

1. Open Settings and go to Windows Update.
2. Select Update history, then Uninstall updates.
3. Find KB5121003 (or the latest cumulative update that includes it) and select Uninstall.
4. Restart the laptop.

Fix 3: Uninstall the update from recovery mode

If Windows will not start, force it into the Windows Recovery Environment by interrupting startup two or three times, then choose Troubleshoot > Advanced options > Uninstall Updates > Uninstall latest quality update. You may be asked for your BitLocker recovery key here. If Windows still will not load, see our guide on what to do when a computer turns on but will not load Windows.

Fix 4: Pause updates temporarily

After uninstalling, Windows may try to reinstall the same update. Go to Settings > Windows Update and choose Pause updates for one or two weeks while Microsoft, HP and Lenovo work on a permanent fix.

Fix 5: Update Lenovo drivers and firmware

Lenovo owners should run Lenovo Vantage or Lenovo System Update to check for new BIOS, embedded controller and power management drivers. Some users report that driver updates alone did not fix the AC drop-outs, but installing official firmware updates is still good practice once a fix becomes available.

Is it the update or a hardware fault?

Not every charging or boot problem this month is caused by KB5121003. Batteries wear out, charging ports loosen and motherboards fail, and misdiagnosing a real fault can be costly. There are also genuine Health Hazards to watch for: a laptop that gets very hot, smells of burning or has a bulging case may have a failing or swollen battery, and should be switched off and checked by a professional immediately rather than kept on charge.

For more help telling them apart, read our guides on hardware vs software power problems, why a laptop battery drains instantly and laptops that power on then shut off. If the fault is physical, we offer laptop battery replacement and laptop charging port repair.

When to call a professional

You should get expert help if:

• The laptop is stuck at the logo or in a repair loop and the steps above do not work
• You see a BitLocker recovery screen and cannot find your key
• A BIOS update was interrupted or the laptop no longer powers on
• The laptop holds important business or personal files that are not backed up
• You manage several computers and need updates handled consistently

Computer Cures is an established, reputable Melbourne IT company with years of experience fixing Windows, BIOS and boot problems. We specialise in HP laptop repairs and Lenovo laptop repairs, as well as operating system installations and repairs and computer not starting repairs. For businesses, our remote support and on-site IT support teams can roll back and manage updates across every device.

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