Why Does My Computer Clock Keep Changing?
First verify the time zone and automatic time settings. A consistent one-hour shift usually points to time zone or daylight-saving configuration; gradual drift can be synchronization trouble; a date that resets after power-off can indicate firmware settings or a failing clock battery.
What to know
- Wrong time and wrong time zone are different problems, so record both before changing settings.
- Automatic synchronization requires a working network and correct system configuration.
- Repeated resets after complete shutdown may require manufacturer service, especially on a desktop or older computer.
A computer clock can be wrong in several distinct ways: it can show the correct minutes but the wrong hour, drift gradually, jump after connecting to a network, or reset to an old date after the machine loses power. The pattern matters because each points to a different layer.
Record the exact pattern
Before changing settings, note the displayed date, time, and time zone. Compare them with a trusted clock. Then restart the computer and check again.
A difference of exactly one or several hours usually suggests the wrong time zone or daylight-saving configuration. A clock that loses a few minutes over days may not be synchronizing. A date that returns to a much older value after shutdown can indicate a firmware or hardware-clock problem.
Check the time zone first
On Windows, open Date and time settings. Microsoft provides separate controls for setting time automatically, setting the time zone automatically, and choosing a zone manually. [1]
Confirm that the selected city or UTC offset matches your location. Automatic time-zone detection may be inaccurate when location services are unavailable, a VPN routes traffic elsewhere, or the computer travels between regions.
On macOS, Date and Time settings control automatic date and time, time zone, and location-based zone selection. Apple recommends using network-provided time when available. [2]
If the computer is stationary, choosing the correct zone manually can be more predictable than leaving a failing automatic-zone feature enabled.
Turn automatic time synchronization back on
Automatic time uses a network time source to correct the system clock. Confirm the computer has internet access, then enable the documented automatic date-and-time setting. On Windows, use the Sync now control when available. On a managed work or school computer, time may be controlled by the organization; do not remove management settings.
A firewall, captive portal, broken network, or long period offline can prevent synchronization. Fix ordinary network access before changing firmware.
Check daylight-saving behavior
When the clock is wrong by one hour near a seasonal change, verify that the selected time zone is correct and that automatic daylight-saving adjustment is enabled where applicable. Do not simply move the clock by one hour while leaving the wrong zone selected, because the error may return during the next change.
Some regions do not observe daylight saving time, and rules can differ by location. Operating-system updates may include time-zone database changes, so install normal updates.
Review dual-boot and virtual-machine behavior
A computer that runs two operating systems may have one system treating the hardware clock as local time and another treating it as UTC. The visible time can jump whenever the machine switches systems. Follow documentation for the exact operating systems rather than repeatedly correcting the clock by hand.
Virtual machines can inherit time from the host or use guest synchronization tools. Check whether only the virtual machine is wrong.
Watch for resets after power loss
The computer keeps basic time in firmware even when the operating system is not running. If the date resets after unplugging a desktop, removing a laptop battery, or leaving the computer off, the firmware clock or its backup battery may be failing.
Other clues include firmware settings that do not persist, boot warnings about time or checksum, and a date that returns to the same old value. Do not open a laptop or compact computer merely to replace a battery without manufacturer instructions. Some clock batteries are soldered, buried, or part of a larger service procedure.
Scan for software causes carefully
Remote-management software, domain policy, security tools, and time-sync utilities can override the ordinary setting. If the problem began after installing a utility, remove or disable only that known program using its documented process.
Malware is not the most common explanation for a wrong clock, but a sudden change alongside other compromise signs warrants a trusted security scan and account review. Avoid downloading a random “clock fixer.”
When to seek service
Arrange manufacturer or repair service when the date resets after power loss, firmware settings will not persist, the computer reports clock errors during startup, or time drifts even while automatic synchronization is functioning on a reliable network.
The practical order is: verify the time zone, enable automatic time, synchronize, update the system, observe behavior after restart and shutdown, and only then suspect hardware.
Limits and cautions
- Menus, firmware behavior, network time policies, and replaceable clock batteries vary by device, operating system, and organization management.
Source notes
- Set time, date, and time zone settings in WindowsMicrosoft Support
- Set the date and time automatically on your MacApple Support
See something wrong or out of date? Report a correction.