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CMOS Checksum Error: Diagnose & How To Fix [ 5 Ways]

Resetting or updating your BIOS should fix this issue convincingly

5 min. read

Updated onOctober 4, 2023

updated onOctober 4, 2023

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Key notes

TheCMOS checksum erroris a conflict between the CMOS and the BIOS that happens when youboot your PC.

When you shut down your PC, the CMOS records a number that must match another that the BIOS generates when you start the computer again.

If these two values don’t match, the PC may return a CMOS checksum error. This is an error detection mechanism referred to as checksum, otherwise known as a redundancy check for picking errors in data.

Why is the CMOS checksum bad?

There are different reasons why a CMOS checksum error – defaults loaded would occur. And different computers deal differently with the error. Let’s look at a few causes of the CMOS checksum error before suggesting a couple of fixes:

How do I fix CMOS checksum errors on Windows 10?

1. Restart the computer

Sometimes abruptly cutting the power to your machine will cause the CMOS checksum error on HP, Dell, and Lenovo the next time you boot up.

Even switching the computer off using the power button without following the normal shutdown procedure can corrupt the BIOS and cause this error to pop up.

If you suspect this could be the reason the error has been OK, follow the computer’s instructions and restart the computer after it finishes booting. The CMOS checksum error should not appear again. Just remember to shut down the correct way next time.

2. Perform a startup repair

In rare cases, the CMOS checksum error after replacing the battery might be due to other startup issues. The quickest way to fix this is to perform a Startup Repair, as shown above.

3. Update the BIOS

Sometimes, the CMOS checksum error may simply be due to outdated BIOS. Updating orflashing the BIOSby checking the manufacturer’s website for the latest version should do the trick.

However, you should be careful while updating your BIOS, as any mistake might be costly. So, ensure you follow the instructions carefully or seek the help of a technician.

4. Reset your BIOS

If you suspect your BIOS has been corrupted by malware or due to a power cut, the best option may be toreset the BIOSto its default or factory settings.

This will also work where the CMOS checksum error occurs after replacing the battery or due to a BIOS update that went wrong. Finally, note that the structure of your BIOS setup page will depend on your PC.

5. Replace the CMOS battery

In some cases, theCMOS battery might be corruptbeyond repair. This small battery on the motherboard provides power to the CMOS, so it remains powered when you switch off the power supply to the computer.

This battery ensures the BIOS loads the correct settings for the computer to start normally. But if it is spoilt, you might keep getting the CMOS checksum error.

Hence, you need to replace the battery to eliminate the error message. However, you need a high level of technical expertise to do this. If you are not sure, it is advised to consult a technician.

The CMOS checksum error can be irritating if you don’t get it fixed. And that irritation will grow into frustration if you fail to find a workable solution to the problem.

Hopefully, the solutions we have discussed here will help you to fix the error and get your PC to behave again. If you still can’t fix the issue after applying the fixes above, you might need to see a technician, as the problem might be caused by hardware damage.

In the same vein, if yourCMOS battery is low, check our detailed guide to fix it quickly.

Feel free to let us know the solution that helped you fix this issue in the comments below.

CMOS Checksum Error: Diagnose & How To Fix [ 5 Ways]#

Why is the CMOS checksum bad?#

How do I fix CMOS checksum errors on Windows 10?#

1. Restart the computer#

2. Perform a startup repair#

3. Update the BIOS#

4. Reset your BIOS#

5. Replace the CMOS battery#