BIOS time and date keep resetting lenovo

 BIOS time and date keep resetting

Symptom:

System date & time was always changed to a default value after restart machine.

Solution:

Enter BIOS, set correct time and date, load BIOS default, then shutdown machine and remove AC adaptor and battery. For un-detachable battery, do the battery reset by battery reset hole or in BIOS. Attach the battery and AC adaptor again and boot the machine, check if the issue fixed.
If problem still exists, replace RTC battery.

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