1. Check whether the CMOS battery needs to be replaced, 2. Ensure that the Windows automatic synchronization time setting is enabled, 3. Enter BIOS/UEFI to manually correct the system time, 4. Advanced users can configure the NTP server. Time errors after Windows computer restart are usually caused by exhaustion of CMOS battery, abnormal time synchronization settings, BIOS time errors or NTP configuration problems. First, try to replace the CR2032 battery on the motherboard and use tools to detect the voltage; if the battery is normal, you need to enable automatic time and time zone synchronization in the system settings and manually test the synchronization function; at the same time, check the time settings in the BIOS and correct the errors; for enterprise environments or advanced users, you can configure Windows time service to specify the time server for synchronization through the command prompt.

Sometimes your Windows PC might reset the date and time to something completely off after a reboot. It's annoying, especially if you rely on accurate timestamps for work or logs. The good news is that it's usually not a serious issue — more like a small misconfiguration or hardware hiccup.

Check the CMOS Battery First

This is the most common cause. Your motherboard has a small battery (like a coin cell) that keeps the system clock running even when the PC is off. If it's dying or dead, the clock resets every time you shut down.

• Try replacing the CMOS battery (usually a CR2032).
• You can check the current battery voltage using tools like HWMonitor (if supported by your hardware).
• A fresh battery should last a few years, so this fix is often long-term.

Sync Time Automatically via Windows Settings

If the battery isn't the problem, Windows might just be failing to sync time properly after boot. Luckily, there are built-in settings to handle that.

Go to:

• Settings > Time & Language > Date & Time
• Make sure “Set time automatically” and “Set time zone automatically” are both turned on.
• Click on "Sync now" under "Synchronize your clock" to test if it works immediately.

Also, make sure your internet connection is stable during boot — Windows needs to reach out to Microsoft's time servers.

Check for BIOS/UEFI Time Settings

Sometimes the issue isn't with Windows at all — the BIOS might be storing the wrong time and passing it along at startup.

• Restart your PC and enter BIOS/UEFI (usually by pressing Delete, F2, or F12 during boot)
• Navigate to the system time/date settings
• Manually correct the time if it's off
• Save and exit

Also, look for any option related to “RTC Alarm Power On” or similar — sometimes these can interfere with the clock if set incorrectly.

Bonus: Advanced NTP Configuration (Optional)

For advanced users or in corporate environments, you might want to tweak the Windows Time service:

• Open Command Prompt as Administrator
• Run w32tm /query /configuration to see current time server settings
• You can change the server using:

   w32tm /config /manualpeerlist:"time.windows.com" /syncfromflags:manual /update

This forces Windows to use a specific time server consistently.

That's about it. Most of the time, it's either the CMOS battery or a sync setting gone rogue. Fix those, and your clock should stay put.

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