Invalid CMOS checksum (Battery replacement solution?)

[oiluj]

Greetings,

I've started experiencing an issue with my laptop, and I'm unsure if replacing the battery could be a solution.

When I power up the laptop, I am prompted with the following message:

The CMOS checksum is invalid. The CMOS will be reset to the default configuration and will be rebooted. Please check your BIOS Setup options to see if they change

CMOS RESET (502)

I press ENTER to reboot the system. Then, the login screen is shown with an old date (March 16th,2025 9:40 P.M) and then it restarts and, in this instance, I am shown a light blue Recovery screen that reads:

It looks like Windows hasn't loaded correctly*. If you'd like to restart and try again, choose 'Restart my PC' below. Otherwise, choose 'See advance repair options' for troubleshooting tools and advanced options. If you don't know which option is right for you, contact someone you trust to help with this.*

Afterward, it is an endless loop of restarting without going beyond the login screen. I've tried to locate the CMOS battery, but I'm unsure if it's powered by the main battery instead. If useful, I replaced my laptop's main battery years ago with a used one, so I'm not sure if replacing it will solve this issue.

Additionally, the laptop cannot remain powered when unplugged. Strangely, when plugged in, the laptop fluctuates from charging (orange light) to charged (white light).

I will greatly appreciate your feedback on this matter.

[Max3Aj]

@oiluj, Welcome to HP Support Community. 

Thank you for posting your query, I will be glad to help you. 
Your issue points to a failing or drained CMOS battery, which is likely causing the invalid checksum error and resetting the date/time upon boot. Since your HP ENVY x360 - 15m-ds0011dx does not have a separate replaceable CMOS battery, it relies on the main battery to retain BIOS settings.

Steps to Fix the Issue:

Confirm the Battery Issue

• Since your laptop cannot remain powered when unplugged and fluctuates between charging states, your main battery is likely faulty.
• A weak or failing main battery can no longer retain BIOS settings, leading to the CMOS error and system instability.

Try a Hard Reset

1. Unplug the charger and remove the battery (if removable).
2. Hold the power button for 30 seconds to discharge any residual power.
3. Reinsert the battery and plug in the charger.
4. Power on the laptop and check if the CMOS error persists.

Update the Date/Time in BIOS

If you can access the BIOS:

1. Press F10 during boot to enter BIOS Setup.
2. Navigate to System Configuration > Date and Time.
3. Set the correct date and time.
4. Save and exit (F10).
5. Restart and check if the error reappears.

Replace the Main Battery

Since your laptop relies on the main battery for CMOS functions, a degraded battery can cause:

• The CMOS checksum error
• The inability to hold BIOS settings
• Power instability

If the issue persists, replace the main battery with a new one, preferably an original HP battery.

Repair Boot Issues (if Windows Still Fails)

If the CMOS issue is resolved but Windows is stuck in a recovery loop, try Startup Repair:

1. Select See advanced repair options.
2. Choose Troubleshoot > Advanced options > Startup Repair.

If startup repair fails, you may need to reinstall Windows after backing up your data.

I hope this helps. 

Take care and have a good day. 

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping! 

Max3Aj

HP Support 

[oiluj]

Dear @Max3Aj,

Thank you very much for such a detailed answer. I will try the procedures suggested, and will update on this post once I have tried everything.

Once again, I truly appreciate the time taken to reply such a detailed answer.

[Max3Aj]

My pleasure @oiluj 🙂

Please do keep us posted. 

Have a nice day! 

Max3Aj

HP Support