CMOS checksum is invalid. CMOS Reset (502)

[new-destop]

This HP All-in-One is only a couple of months old. Brand new, just out of the box it displayed the CMOS checksum is invalid. CMOS Reset (502) error message, but then restarted and seemed to operate normally, unless it lost all power. (Shutting down PC with power supply still hooked up did not allow error to pop up.) I also recently was having problems with the PC unable to wake from sleep mode, but yesterday I downloaded a new HP Support upgrade, and used it to reset bios to default and PC now wakes from sleep mode OK.

But I still get the CMOS checksum error from a cold start (after PC has had power removed completely). I can read the BIOS version/date, but how do I know if it is correct? Instant Chat is wanting me to send PC in for repair, but I would rather fix it myself, if possible.

Thanks!

[Grzwacz]

Greetings,

Welcome to the forum.

I am not a HP employee.

A BIOS checksum error message is not good to see.

Your PC may fail to POST at some point in the future.

I would use the warranty.

You could pull the CR2032 motherboard (MB) battery, let the PC sit for about 15 minutes, then reinstall the battery. Or install a new MB battery. This will reset CMOS. Or try resetting the BIOS to defaults.

Continuing checksum error messages after doing the above may require HP intervention.

Did you add any new hardware recently?

Regards

[new-destop]

Thank you for your advice. I have not installed any new hardware. Resetting BIOS to Default cured the problem I had with the PC locking up, with no response from mouse or keyboard, now booting from sleep mode OK, although the BIOS version and date remained unchanged. Since this is an All-in-One, there are no screws or obvious fasteners to disassemble the case, I will probably send the unit back for repair. I have had HP desktops since 1998, and this will be the first time I will have to send one in for repair.

Thank you for your advice!

[Grzwacz · Accepted solution]

Hi New_Destop,

You're very welcome.

What BIOS version are you running?

There is a BIOS update, F15 Rev.A, dated May 2019, available for download at this (Link).

BIOS updates can sometimes fix stuff like this. Let the BIOS update do its thing if you decide to do the update. Be patient.

BIOS updates can make things worse if the PC is shut down during the update or you lose AC power.

I would not disassemble this product when you are in warranty. Let HP deal with this.

Regards

[Grzwacz]

Hi New-Destop,

Did the BIOS update link in previous post fix the BIOS checksum error?

Regards

[new-destop]

I no longer have the pc, I sent it in to HP for repairs.

Thanks!

[Grzwacz]

Hi,

Okay.

Good to know.

Regards