How to Fix CMOS Checksum Error in Windows 10

CMOS or Complementary Metal Oxide Semiconductor is a semiconductor chip inside a PC that stores information like BIOS settings, time and date, etc. Whenever a data conflict between the BIOS and CMOS data occurs, you will get the CMOS checksum error.

Why am I getting CMOS checksum error?

So, what are the reasons that could lead to conflict between BIOS and CMOS data on your PC? Well, there are various issues that can trigger the CMOS checksum error, some of which can be easily fixed, and some may even require hardware replacement. Let us take a look:

Improper PC Shutdown

If you did not shut down your PC properly, you may get the checksum error. This is because an improper shutdown did not give your CPU enough time to generate a checksum number. And as we know, if there’s a conflict between checksum numbers, you will get this error.

Make sure to shut down your PC properly by going to the Power option in the Start menu. Once the shutdown process initiates, make sure to unplug your PC from the power source only when the monitor and the CPU switch off on their own.

CMOS Battery might be dead

The CMOS chip in your PC does not run on the standard power input but requires an additional small battery to operate. When the charge in the battery completely drains out, the CMOS is unable to generate a checksum number. This again leads to a conflict between the BIOS and CMOS checksum values causing the checksum error.

Corrupt / Outdated BIOS

Issues with the BIOS on your PC could also be the reason why you are getting the error. If the BIOS installed on your PC is not up to date, it could conflict with the latest OS versions. Although it’s a rare occurrence, you may also get this error because of a corrupt BIOS.

Power Surge

If there’s a power surge and your PC shuts down unexpectedly, you can get the checksum error because of the CMOS being unable to generate a checksum number.

If your Motherboard is Damaged

A motherboard that has taken physical damage could lead to various issues including the CMOS checksum error. At times, even small damage could lead to things going downhill.

Now that you know what are the reasons behind this error, let us find out how to fix CMOS checksum error in Windows 10.

Solution 1: Restart Your PC

The first step that you should take in order to resolve this issue is restarting your PC. As mentioned earlier, an improper shutdown could lead to conflict between your PC’s CMOS and BIOS. So, go ahead restart your PC properly and see if this resolves the issue.

In most cases, a simple restart could do the trick, but if it doesn’t, the reason behind the issue could be something else.

Solution 2: Check if the CMOS battery is placed properly


It is important for the CMOS to run at all times while you operate your computer. As we know that the CMOS operates on a tiny battery, any issues with it could lead to issues like the CMOS checksum error.

It might be possible that the CMOS battery has been displaced from its position and causing all the trouble. Although minor bumps barely could displace the battery, you will need to make sure about it.

If you are using a desktop PC, locating the CMOS is really simple. It is a small battery placed on the CPU’s motherboard. However, it could be an issue finding the battery in laptops. For this, you can always Google about the CMOS battery location on your laptop by entering your laptop’s brand and model name.

If you see the battery needs to be adjusted, fix it to the defined position, then restart your PC. This might take care of the issue.

Solution 3: Replace CMOS Battery

After checking on the CMOS Battery position to see whether it’s placed properly if you are still getting the checksum error in Windows 10, then it might be possible that the CMOS battery has run out of charge.

It is advised always to keep a couple of CMOS battery handy. They do not cost much and replacing them is not a very daunting task. Anyone with minimum knowledge of PC hardware can go ahead with this solution.

Go ahead and replace the battery with a new one. While you do that, make sure you have placed the battery perfectly at its spot.

After doing so, restart your PC and see if the CMOS checksum error was fixed. If not, try the next solution.

Solution 4: By Resetting your PC’s BIOS

Resetting your PC’s BIOS back to factory settings could help you get rid of the issue. It could be possible that the BIOS on your PC was corrupted. Events like a sudden power surge or even a malware attack could lead to your motherboard getting corrupt or malfunction.

In order to eliminate this probability, you can carry out a BIOS reset on your PC.  Doing so will render the BIOS fresh as new and might fix the issue. But how to reset BIOS?

For this, you will need to enter the BIOS setup on your computer.

Restart your PC and as soon as it powers on, you will need to press the F2, F10, F11, or F12 keys on your keyboard. The key to press to enter setup is defined by the manufacturer and you can view the key to press as soon as the startup screen appears on the monitor.

Once you enter the BIOS settings, you will find the option to reset the BIOS. Press the specified key to carry out the reset. The reset key again varies across manufacturers and if you cannot find the option, I advise you to take a look at your motherboard’s user manual.

Once you have figured out how, go ahead with a BIOS reset. After the reset, restart your PC and see if you are still getting the CMOS checksum error.

Solution 5: By Updating your PC’s BIOS

Your PC may fail to reboot and even face issues if your BIOS is outdated. In such a case, you will need to make sure that the updated version of BIOS is installed on your PC. If you are not sure, you can always proceed with updating the BIOS. If an update is available, proceed with it, if not, try out the next step.

There are a couple of methods that you can follow to update the BIOS on your PC. The first one is through the BIOS setup menu. Follow the steps provided in the previous method to enter the BIOS menu. When there, follow the motherboard’s user manual to update the BIOS to the latest version. That is one way to update the BIOS.

The other way to update BIOS on your PC is by visiting the manufacturer’s website of the motherboard you are using. Here, select the motherboard model you have installed on your PC and download the latest version of the BIOS update. After downloading the update, run it on your PC to initiate BIOS update.

Once you have successfully updated the BIOS on your PC, go ahead and restart it. After the PC restarts successfully, see that if you are getting the CMOS checksum error.

Solution 6: Consult a Computer Technician

Your PC’s motherboard is anything but a simple device to deal with. If none of the above methods worked for you to get rid of the CMOS checksum error in Windows 10, you might want to consult a technician who is good with computers, especially motherboards.

A technician can go through your PC’s hardware as well as software to observe what exactly is causing the checksum error to occur on your PC.

Although its quite evident that some of the technicians may go ahead and try to cheat you, I recommend consulting someone (maybe a friend) who is good at computers first who might have experience dealing with motherboard issues.

The maximum expenditure that you can expect while dealing with this issue with the help of a technician is the cost of the motherboard along with service charges.

Be wary of the technicians who could be ripping you off. Always, negotiate the price of repair required to get your PC back to work again without any issues.

Consulting the service center of the device’s manufacturer is always a wise choice.

Solution 7: By Replacing Motherboard

Make sure to check your PC for physical damage to the motherboard. If you are using a desktop PC, the chances of getting the motherboard damaged is higher than it usually is with laptops. Whatever the case may be, if the above methods did not fix the issue, go ahead and give your PC’smotherboard a physical check and look out for damages, even the minute ones.

If you find any damage that compromises any of the motherboard’s chips or equipments, go ahead and get it checked by a technician. If there’s nothing that can be done to salvage the motherboard, go ahead and replace it. But, always make sure that the motherboard actually needs to be replaced.

Closing Words

In the end, the reason behind you getting the CMOS checksum error on your PC should mostly be issues with the motherboard battery. It’s hardly the case that you will need any sort of replacement. But if you do and the situations justify it, you will need to consider the replacement.