There are usually three main reasons that a CMOS Checksum Bad Error has occurred. They include:
- CMOS Battery may not be functioning properly. The battery life may have expired.
- Your BIOS may have been updated (either by user or possibly a virus)
- The computer may not have been shut down properly e.g. shutting off the computer's main power without first shutting down the computer (MS Windows requires you to shut down your computer before shutting off the power).
Solutions to CMOS Checksum Bad Error
The CMOS Checksum Bad Error can be fixed easily by following the listed steps carefully.
CMOS Battery may not be functioning properly
If you suspect that your CMOS battery is not functioning properly, you can easily change it. Before changing your battery, reboot your computer to make sure that the error still exists. If it does, go into your CMOS and write down all of the settings. If all the settings are lost, you can usually retrieve them from your computer manufacturer. Now locate the battery and remove it, you might need to consult your computer’s manual or technical support to remove your battery (the battery a flat, shiny silver colored and coin-shaped). Take down the CMOS battery’s information such as volt, size, etc. Once you have your new battery, you can replace it and reenter your CMOS settings. If your battery was the cause of the CMOS Checksum Bad Error, you should have solved the problem.
Your BIOS may have been updated
If your BIOS have been updated recently, your CMOS settings may have reset. Make sure that the values entered in the BIOS are correct or simply reset them to the default settings. If you believe that a virus has updated your BIOS settings, run a virus scan and make sure that the BIOS settings are back to the default.
The Computer may not have been shut down properly
Sometimes when running MS Windows, if you shut down your computer without first properly shutting down your operating system, it will corrupt the CMOS settings causing the CMOS Checksum Bad Error. You can easily avoid this error by making sure that you completely shut down your computer properly before turning off the main power. Usually this entails going into the Start Menu, clicking on Turn Off Computer/ Shut Down. If improper shutdown was the cause of the error, you may have solved the issue