In this article, we’ll consider why the system clock displays incorrect time and date after a shutdown, restart or resuming from hibernation of a laptop/computer/server. Time is reset each time and you have to set it manually. We’ll dwell on the most typical case: a rundown BIOS battery and more interesting ones involving Windows/Linux dual boot on one computer, and a firmware bug on HPE ProLiant G9 /G8 servers with Windows Server OS.

System Not Saving Data/Time Due to Weak BIOS/CMOS Battery

The typical answer to the question “Why are the time and date reset on my computer after reboot?” is the BIOS (CMOS) battery rundown. This battery is responsible for keeping BIOS/UEFI settings when your computer or laptop is unplugged, and provides autonomous operations of the built-in hardware clock.

If the battery has run down, when the motherboard is not powered, BIOS cannot keep its settings and all of them are reset, including current date and time. If your computer is quite old, it is very likely that your battery is dead. We strongly recommend to replace it. It is not hard, and the process doesn’t require any special engineering skills. In most home and even enterprise devices a standard 3V CR2032 battery is used in BIOS.

If the battery replacement hasn’t helped, check the state of the jumper used to reset BIOS settings (The jumper is located close to the battery bay and is marked as CMOS / CLEAR / RESET). Somebody may have left it in the RESET position. Thus, each time when your motherboard is powered, BIOS settings are reset. Move the jumper to its normal position.

The next option is to update BIOS firmware of your motherboard. See how to do it on the website of your hardware vendor. Newer firmware often has different bugs fixed.

Windows: Set Clock Synchronization with time.windows.com

If your date/time settings in Windows are constantly changing, first of all you should check the current time zone settings and the parameters of time synchronization with the external time server. In Windows 10, you can see the current time settings in the Control Panel -> Clock and Region -> Date and Time. In this example, you can see, that the time zone UTC + 01 is specified, and Daylight Saving Time is enabled.

If your computer is not joined to the AD domain, check its time synchronization settings with the external time source (NTP time server). To do it, click Internet Time tab and make sure that the automatic synchronization with time.windows.com server is set.

Troubleshooting time synchronization for AD domain-joined computers

If your computer is part of an Active Directory domain, you need to understand the architecture of time synchronization in the AD domain.

The following time synchronization scheme is used in the Active Directory domain:

• The root domain controller in the AD forest, to which the FSMO role of the PDC emulator belongs, is a time source for all other DCs of this domain;
• Other DCs synchronize time with PDC;
• Ordinary domain members (servers and workstations) synchronize time with the nearest available domain controller according to the AD topology.

Root PDC can synchronize its time with both an external source and with itself (by default).

You can find a domain controller with the PDC role with the command:

netdom /query fsmo

To configure time synchronization with an external NTP server on the PDC, the following commands are used.

Configure external time sources:

w32tm /config /manualpeerlist:"0.nl.pool.ntp.org,0x1 1.nl.pool.ntp.org,0x1 2.nl.pool.ntp.org,0x1 3.nl.pool.ntp.org,0x1"

Make this DC a reliable time source for the clients:

w32tm /config /reliable:yes

Restart w32 time server to synchronize DC time with nl.pool.ntp.org time servers:

net stop w32time && net start w32time

You can view the synchronization source and status:

w32tm /query /peers

Start synchronization in manual mode:

w32tm /resync /rediscover