Troubleshoot Inaccurate System Date & Time

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• If the date and time are not correctly synchronized with other computers on the network or on the Internet:
  • security systems such as authentication will not work
  • utilities such as backup programs and schedulers will be unreliable

Real Time Clock (RTC)

The real time clock (RTC) is a part of the chipset that keeps track of the calendar date and time.

• runs on battery power when the computer is turned off
• RTC battery is a coin cell lithium battery
• If the date or time displayed in the system firmware setup program is inaccurate, it can be a sign that the RTC battery is failing
• replace it with the same size and type
• Typically, the coin cell type is CR2032, but check the motherboard documentation

Info

• RTC battery is also often called the CMOS battery
• On older computers, system firmware custom settings were saved to CMOS RAM
• CMOS stands for complementary metal-oxide semiconductor
  • describes the manufacturing process used to make the RAM chip
• CMOS requires battery backup to save data
• On current motherboards, configuration data is stored in a non-volatile RAM (NVRAM) chip (flash memory), rather than in CMOS RAM
• Flash memory does not require battery backup