Dealing with CMOS Checksum

Generally, CMOS checksum error comes up as "CMOS checksum invalid, default values loaded". It happens due to corrupted files stored in BIOS or if it the BIOS settings itself are wrong. We may get the error with while the booting takes place. Actually, checksum is a calculation that generates a specific unit from a particular cluster of data. This unit is stored in CMOS which is known as complementary metal oxide semiconductor. System will not boot up without CMOS checksum.

The most common CMOS checksum symptoms are: Computer will not boot up or we may start getting errors during boot up from the motherboard. If the BIOS appears with the error "CMOS Checksum Error', 'CMOS settings wrong', 'CMOS battery error' and or 'CMOS read error' then we would get a blank screen during booting. We may not able to save the file or program. Then while installing a program and then the next time if we turn on the computer if it is not there and we may need to reinstall it. Sometime the computer shuts down without a prompt. All these symptoms indicate CMOS checksum error.

Usually, CMOS checksum comes up when the battery on the mother board is out of charge or gone bad. The error may also come up if the BIOS have updated or any change like hardware installations, incompatibilities, or BIOS flashing has taken place. However, it may also happen due to viruses like AntiCMOS. This happens if we don’t shutdown the computer properly. In this case, we should try to reboot the system. If still there is no change, we should try to replace the CMOS battery. After this we should update the BIOS itself by installing the latest BIOS program to prohibit CMOS checksum or else we need to call the motherboard vendor.