CMOS checksum error
BIOS settings reset at every boot
What it means
The small battery that keeps BIOS settings and the clock alive is empty, or the settings were corrupted.
Common causes
- A dead CR2032 battery
- A BIOS update or failed overclock
- A board that loses standby power
How to fix it
- Replace the CR2032 battery with the PC unplugged, then set the date and time.
- Load optimised defaults in the BIOS and save before changing anything else.
- If the error returns with a new battery, check the battery holder and the board's standby circuit.
- Reapply XMP/EXPO and fan curves only after the clock survives a power cycle.