EasyAbout 6 minutesBoth

The clock keeps showing the wrong time

My computer clock resets or is hours off. Why and how do I fix it?

CF

Written by The CommonFixes team · fact checked by CommonFixes review desk

Last updated

Short answer

Either the time zone is wrong, the internet time sync is failing, or the small coin battery on the motherboard that keeps time while the machine is off has died. The quickest thing to try first: turn on automatic time — Settings, Time and language, Date and time. Switch on Set time automatically and Set time zone automatically, then press Sync now. Most people are done in about 6 minutes.

Full walkthrough below: 4 steps for Windows and Mac, rated easy.

Sounds like this

  • Websites warn the certificate is not valid yet
  • Time jumps after every restart
  • Wrong date on saved files

Why it happens

Either the time zone is wrong, the internet time sync is failing, or the small coin battery on the motherboard that keeps time while the machine is off has died.

Work through these in order

0% done
  1. 1

    Turn on automatic time

    Settings, Time and language, Date and time. Switch on Set time automatically and Set time zone automatically, then press Sync now.

  2. 2

    Fix the time zone by hand

    If the hours are off by a whole number but minutes are right, the time zone is wrong. Pick your city manually and turn off automatic time zone.

  3. 3

    Restart the time service

    Open Services, find Windows Time, set Startup type to Automatic and click Start.

  4. 4

    Replace the CMOS battery

    If the clock resets to a date years ago every time you unplug the machine, the CR2032 coin cell inside is flat. It costs very little and takes minutes to swap on a desktop.

If none of that worked

On a laptop the coin cell is under the keyboard or motherboard. A repair shop will replace it quickly, and it is worth doing because a wrong clock breaks secure websites and email.

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Who wrote this and how we checked it

CF

The CommonFixes team

Writer and researcher

We are a small group of people who spend our days repairing laptops and desktops for family, friends and small offices. Every guide here starts with a problem someone actually brought to us, and we only write down the steps that put the machine right.

  • Everyday repairs
  • Windows and Mac
  • Plain language
RD

CommonFixes review desk

Technical editor

Before a guide goes live, a second person walks through it on a real machine and checks each instruction against the maker's own support pages. Anything we cannot confirm is removed rather than guessed at.

  • Fact checking
  • Safety warnings
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This guide was last updated on 10 August 2026. If a step no longer matches what you see on screen, tell us on the contact page and we will test it again.

A gentle reminder: back up anything you cannot afford to lose before major repairs. If a step ever feels risky, stop and ask a technician. There is no shame in that.