Fix CMOS Checksum Error on Windows 10, 8.1, 8, 7, Vista, XP

Jun. 24, 2022 / Updated by Helia to Windows Driver Solutions

CMOS checksum error is an unusual computer error which occurs during the system startup. The checksum error is often related to the BIOS (Basic Input/Output System), the firstly running program once you power on the computer. BIOS will initialize and test the hardware, such as the CPU, memory, keyboard, mouse, etc. Complementary Metal-Oxide Semiconductor (CMOS) is a battery powered semiconductor chip on the motherboard, which contains data related to the BIOS.

If the CMOS battery is used up, or if the BIOS values have become corrupted, which makes CMOS unable to retain data, then you’ll get the checksum error while the Windows machine is starting up. In this case, you may receive an error message on the black screen as you can see in the picture below:

“Diskette drive 0 seek failure

CMOS checksum error – Defaults loaded

Press F1 to continue, F2 to enter SETUP”


Now that we’ve learned about the culprits that trigger the CMOS checksum error on the Windows, it’s time to take solutions to fix the error.

Top 2 Ways to Fix CMOS Checksum Error on Windows PC

In this Windows guide, we’ll walk you through top 2 ways to troubleshoot the checksum error, especially the “CMOS checksum error defaults loaded”.

Way 1. Replace the CMOS Battery to Fix the Checksum Error

Most of the computers use the common button battery, namely the battery in model CR2032 3V. You can purchase such battery easily in any convenience stores. If you’ve kept your computer working for over 5 years, it’s recommended to replace the CMOS battery. This is how to make it:

1. Prepare a new CMOS battery.

2. Turn off the computer and cut off the power supply for the machine.

3. Remove the computer case and locate the old battery on the motherboard.

4. Take off the old CMOS battery.

5. Insert the new battery into the battery socket and make sure it is firmly right in the place like the old one.


If you can’t replace the CMOS battery by yourself, it is better to ask some computer technicians for help.

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Way 2. Reset the BIOS and Solve the “CMOS Checksum Error – Defaults Loaded” Issue

Also, try resetting the BIOS values when you encounter the CMOS checksum error – Defaults loaded problem.

1. Boot the computer to the black screen with the checksum error.

2. When seeing the “Press F1 to continue, F2 to enter SETUP” message, hit the F2 key to enter the BIOS. (You may need to press other keys, for example, the key Del, according to your BIOS.)

3. Read the keys usage information on the screen and select the Load Defaults. (Or select the option that works for defaulting the BIOS.)


4. If the system notice you “Load BIOS Defaults(Y/N)?”, then press the Y key and the Enter.

5. After entering the Windows, turn off the computer and restart to see if the problem still persists.

6. If it doesn’t fix the problem, enter the BIOS again.

7. Select the Standard CMOS Features.

8. Check the Date and Time. If they are incorrect, modify the values and save the changes.

9. Check the SATA or Drive. If you have no diskette drive on the computer, you can select Disable/None/Not Detected to stop the diskette drive scanning.

10. Save the changes and exit the BIOS.


Now you can boot to Windows desktop and continue your office work as before.

Note: Different BIOS interface has different option description. Make sure you’ve select the similar options.

See Also:

Update Drivers to Prevent the CMOS Checksum Error

In order to prevent the CMOS checksum error annoy you by accident, you also need to update your device drivers. Driver Talent is a useful Windows driver update and download utility for you to update drivers. It offers the latest official and WHQL drivers and helps to get the Windows back on track and run more securely. You can click the button below to get the driver updates directly.

Download Now

Here are 3 easy steps to update your deivce drivers:

1. Click the Scan to detect all the outdated, missing or broken drivers.

2. Click the Update to download and install the best-matched drviers for your devices.

3. Perform a restart to make the changes take effect.



1. Outdated Windows drivers may cause computer problems like 100% disk usage, unidentified network, mouse and keyboard not working, etc. So it’s recommended to use Driver Talent to update the drivers regularly.

2. Don’t forget to create a system restore point and backup important drivers so that you can restore the system and the drivers once the computer runs into other serious problems.

That's it. Hope that after performing these solutions, the startup black screen will disappear and that you won't receive the “CMOS checksum error – Defaults loaded”. If you still fail to troubleshoot the checksum error on your Windows 10, 8.1, 8, 7, Vista or XP computer, please drop a line below, or click the left menu for help, or go to OSToto Official forum for more solutions.

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