Summary

A clock that is a few minutes out looks harmless and is not. Sign-in tokens, multi-factor codes, and website security certificates are all validated against the time, so a drifting clock breaks them one after another with error messages that never mention the clock. This article gets the time right, forces a sync, clears the failures the wrong time caused, and covers what to do when a work computer keeps drifting anyway.

Symptoms

• Your authenticator app codes are rejected as incorrect, even though you typed them correctly and quickly.
• Sign-in to Microsoft 365 or your work account fails repeatedly with no useful explanation.
• Websites that worked yesterday show Your connection is not private or NET::ERR_CERT_DATE_INVALID.
• Calendar appointments appear an hour or several hours away from when they were booked.
• Email arrives with timestamps that put replies before the messages they answer.
• The clock in the taskbar is right but the date is wrong, or vice versa.
• The clock is correct while the computer is running and wrong again after every shutdown.

In this guide

• 1. Check the Time, Date, and Time Zone
• 2. Turn On Automatic Time and Time Zone
• 3. Force a Sync With the Time Server
• 4. Set the Time Zone Manually
• 5. Fix a Clock That Resets Every Time You Restart
• 6. Clear the Sign-In, MFA, and Certificate Errors the Clock Caused
• 7. Report a Work Computer That Keeps Drifting

Before You Start

• Windows 11 or Windows 10.
• No admin rights are needed for Steps 1 through 4 on a personal or unmanaged PC.
• On a company-managed work computer, the time settings are often locked by policy. Step 7 covers that case.

Instructions

1. Check the Time, Date, and Time Zone

Read all three values before changing anything. The time zone is wrong more often than the clock, and the two failures need different fixes.

1. Right-click the clock in the bottom-right corner of the taskbar and select Adjust date and time. The Date & time page opens in Settings. You can also reach it through Settings > Time & language > Date & time.
2. Read the large Current date and time value at the top of the page. Compare it against a phone or a watch, to the minute.
3. Read the Time zone dropdown below it. It shows an entry such as (UTC-05:00) Eastern Time (US & Canada). Confirm it names the region you are actually in.
4. Work out which of the two is wrong:
   • The time is out by a whole number of hours and the minutes are correct — the time zone is wrong. Go to Step 4.
   • The time is out by seconds or a few minutes — the clock has drifted. Go to Step 2.
   • The date is wrong by months or years — this is a hardware symptom. Go to Step 5.

Note: Windows shows one clock but stores two values: the moment in universal time, and your offset from it. A meeting that lands three hours early is an offset problem, and setting the clock by hand fixes the display while leaving every calendar entry wrong.

2. Turn On Automatic Time and Time Zone

Windows can take the time from an internet time server every few days and keep itself accurate to well under a second. On a healthy PC this is all you need.

1. On the Date & time page in Settings, find the toggle labeled Set time automatically.
2. If it is already On, switch it Off, wait three seconds, and switch it back On. This forces Windows to contact the time server rather than trusting its stored value.
3. Set Set time zone automatically to On as well. Windows then updates your zone when you travel.
4. Set Adjust for daylight saving time automatically to On if the row is present. It only appears for time zones that observe daylight saving.
5. Watch the Current date and time value at the top of the page. It corrects itself within a few seconds.

Note: Set time zone automatically relies on location services. If the toggle is greyed out, open Settings > Privacy & security > Location and turn Location services on. On a work computer that setting is often disabled by policy, in which case set the zone by hand using Step 4 — the manual zone works exactly as well.

3. Force a Sync With the Time Server

The Sync now button does more than fix the clock: it reports whether the sync succeeded, which tells you whether the automatic setting is working at all.

1. On the Date & time page, scroll to the Additional settings section. On Windows 10 the equivalent section is headed Synchronize your clock.
2. Read the line reading Last successful time synchronization. A date from weeks ago means automatic sync has been failing silently.
3. Click Sync now.
4. Watch for the result beside the button:
   • The Last successful time synchronization date updates to now — the sync worked and the clock is correct.
   • A red message appears, typically An error occurred while Windows was synchronizing with time.windows.com — the sync was blocked. Continue to the next point.
5. If the sync failed, check the Time server dropdown in the same section. On a personal PC it reads time.windows.com. Select time.nist.gov from the dropdown instead and click Sync now again. Some networks block one server and allow the other.
6. If both servers fail on a work computer, stop here and go to Step 7. Outbound time traffic is usually blocked deliberately on a corporate network, because managed PCs are meant to take their time from the company's own servers.

Verification: Open https://time.is in a browser. The page compares your computer's clock against an authoritative source and states the difference in seconds. Anything under a second is fine.

4. Set the Time Zone Manually

Use this when automatic detection is unavailable, or when the automatic zone is wrong because you are working from a different country.

1. On the Date & time page, set Set time zone automatically to Off. The Time zone dropdown becomes selectable.
2. Click the Time zone dropdown. A long list opens, sorted by UTC offset.
3. Select the entry naming your region, not merely one with the right offset. (UTC+00:00) Dublin, Edinburgh, Lisbon, London and (UTC+00:00) Monrovia, Reykjavik share an offset today and behave differently when daylight saving starts.
4. Confirm the Current date and time value at the top of the page now matches your watch.
5. Leave Set time automatically on. The zone and the clock are separate settings, and you want Windows still correcting the clock itself.

Tip: After a time zone change, close and reopen Outlook and Teams. Both cache the zone at startup, so appointments continue to display at the old offset until they restart.

5. Fix a Clock That Resets Every Time You Restart

A clock that corrects itself while you work and is wrong again next morning has one of two causes, and neither is a Windows setting.

A failing motherboard battery. A coin-cell battery on the motherboard keeps the clock running while the machine is unplugged. When it weakens, the clock resets on every cold start, often to a default date years in the past.

1. Shut the computer down fully — choose Shut down, not Restart — and leave it off for ten minutes.
2. Start it and read the clock before signing in, on the lock screen.
3. A clock that is wildly wrong at that point, and correct a minute after signing in, confirms the battery. Windows is repairing the time after boot, and the hardware is losing it before boot.
4. On a personal desktop this is an inexpensive part. On a work machine, raise a hardware ticket using the wording in Step 7.

A dual-boot conflict. If the machine also runs Linux, the two systems disagree about what the hardware clock means. Windows stores local time in it; Linux stores universal time. Each boot shifts the clock by your offset from UTC.

1. Confirm the pattern: the clock is wrong by exactly your time zone offset, and only after booting the other operating system.
2. The supported fix is to set the other system to store local time rather than changing Windows. Its own documentation covers the setting.
3. As a stopgap, run Sync now from Step 3 after each switch between systems.

6. Clear the Sign-In, MFA, and Certificate Errors the Clock Caused

Fixing the clock does not always clear what the wrong clock broke. Work through whichever of these you hit.

Websites showing certificate errors. Every HTTPS certificate carries a start date and an expiry date, and your browser checks both against your computer's clock. A clock set to the wrong year makes a valid certificate look expired or not yet issued.

1. Close every browser window completely, then reopen the browser. Browsers cache certificate validation results for the session.
2. Reload the site. The warning is gone.
3. If the error persists on a correct clock, the certificate itself is the problem. See How to Fix the "NET::ERR_CERT_AUTHORITY_INVALID" Browser Error.

Authenticator codes rejected. The six-digit codes are time-based: your phone and the server each derive the same code from the current time in 30-second windows, without ever exchanging it. A clock that is more than about 30 seconds out on either side produces codes that do not match.

1. Check the clock on your phone, not your PC. The code is generated on the phone, so the phone's time is what matters.
2. On the phone, turn on automatic network time. On Android this is Settings > System > Date & time > Set time automatically; on iPhone it is Settings > General > Date & Time > Set Automatically.
3. In Google Authenticator specifically, open the three-dot menu, then Settings > Time correction for codes > Sync now.
4. Request a fresh code and use it within its 30-second window. For anything still failing, see How to Fix Microsoft or Google Authenticator Not Working.

Sign-in still refused. Sign-in tokens are stamped with an issue time and rejected outside a narrow window, so failures continue until the stale ones are discarded.

1. Sign out of the affected application completely rather than closing it.
2. Lock the PC with Windows + L and sign in again. This requests fresh tokens against the corrected clock.
3. If sign-in still fails, work through How to Fix Windows Sign-In Errors — PIN, Password, and Windows Hello Issues.

7. Report a Work Computer That Keeps Drifting

A computer joined to a company domain does not use time.windows.com. It takes its time from a domain controller, which takes it from the company's own time source, and that chain is what keeps every machine on the network within seconds of each other. When it breaks, Set time automatically stays on and the clock drifts regardless — there is no setting on your PC that fixes it.

To confirm your PC is domain-joined:

1. Open Settings > Accounts > Access work or school. A Connected to entry naming your organization means the PC is managed.
2. Note your device name from Settings > System > About, on the Device name line.
3. Note the Last successful time synchronization date from Step 3, and the exact text of any sync error.

Then raise a ticket. Tell IT:

"My computer's clock drifts by the number of minutes even with Set time automatically switched on, and Sync now fails with the message the exact error text. Device name: your device name. The device is domain-joined and the last successful time synchronization was the date shown in Settings. The drift is causing MFA codes and certificate checks to fail. Please check whether the Windows Time service on this device is syncing from the domain controller."

If the clock resets on every cold start, as in Step 5, send this instead:

"The clock on my computer resets to the wrong date it shows every time it is shut down overnight, and corrects itself a minute after I sign in. Device name: your device name. This pattern points to a failed CMOS battery on the motherboard. Please arrange a hardware check."

For help writing the rest of the ticket, see How to Submit an Effective IT Support Ticket.

Troubleshooting

WARNING

Turning Set time automatically off and typing the time by hand hides the symptom and leaves the cause running. A manually set clock drifts again within days, and the failures it causes — rejected MFA codes, refused sign-ins, certificate warnings — never point back at the clock. Fix the sync instead.

Symptom / Error	Potential Cause	Solution
Time is out by an exact number of hours	Wrong time zone, not a wrong clock	Set the correct zone in the Time zone dropdown (Step 4). Restart Outlook and Teams afterwards.
An error occurred while Windows was synchronizing with time.windows.com	Time traffic blocked by the network	Switch the Time server dropdown to time.nist.gov and click Sync now (Step 3). On a work network, use Step 7.
Set time zone automatically is greyed out	Location services are off	Turn on Location services under Settings > Privacy & security > Location, or set the zone by hand (Step 4).
Clock is wrong again after every shutdown	Failing motherboard battery	Confirm with the cold-start test in Step 5, then raise a hardware ticket using the second template in Step 7.
NET::ERR_CERT_DATE_INVALID on sites that worked yesterday	Clock outside the certificate's validity dates	Correct the clock (Steps 2 and 3), then close and reopen the browser completely (Step 6).
Authenticator codes rejected on the first try, every try	The phone's clock has drifted	Turn on automatic network time on the phone and run the time correction (Step 6). The PC's clock is not involved.
Time settings appear locked or greyed out	Managed by IT policy	Expected on a company-managed device. Send IT the first template in Step 7 rather than working around it.

Related Articles

• How to Fix Microsoft or Google Authenticator Not Working
• How to Fix Windows Sign-In Errors — PIN, Password, and Windows Hello Issues
• How to Fix the "NET::ERR_CERT_AUTHORITY_INVALID" Browser Error
• Understanding Windows Updates — What They Are and Why They Matter
• How to Submit an Effective IT Support Ticket

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