Windows PC Clock

[#1]

So why does my network connected Windows PC consistently show clock time at least 5 minutes ahead? A few seconds here or there would not surprise me, but 5 minutes or more? 😦

[#2]

My guess would be that your Windows PC has it's NTP time source set to fetch the time from your router,  but your router isn't correctly configured to update regularly from an internet atomic clock NTP server (other than maybe after router reboot, or when daylight saving changes twice a year). 

Because the router's onboard time keeping crystal (that maintains local time) isn't perfectly accurate, then over time the router's current time is drifting, and your PC's clock is tracking that drift.

1. If you login to your router's GUI, does it show the current time anywhere ? (and is it 5 minutes adrift)
2. Does your router have setting for a user selectable NTP server ?
3. Check in Windows what it's NTP source is,  I suspect it might be automatically set by DHCP from the router.

If you are playing with your router and/or PC's NTP settings, you can see how far out it is by going here - https://time.is/ 

The other possibility is that your router used to use  ntp.plus.net  which has been decommissioned,  and therefore your router isn't getting updates because there is no NTP server listening for update requests.  I don't believe BT have a reliable alternative NTP server that you could use instead.

If your router and/or PC does have configurable NTP server settings, try using  uk.pool.ntp.org 

or for more information have a read of this - https://www.ntppool.org/zone/uk 

[#3 · Accepted solution]

@pvmb 

I have a very vague and distanced memory of a bug in the Plusnet firewall (not the router one) that was causing the router to fail to pick up the NTP server. I believed this to have been fixed. I seem to recall that in my case it went away for no apparent reason when I switched off the no longer required firewall. This additional firewall was a no longer needed throw back to the dial up days and hasn’t been available to new subscribers for years.

Getting the network time is becoming increasingly important as I understand that it is instrumental in synchronising single use 2FA passwords.

[#4]

Yes @Baldrick1 is right,

having the online firewall set to "HIGH" did block time updates in Windows, setting it to "LOW" or "OFF" works.

[#5]

...Thanks for all the suggestions.

Looking into this, the simple answer is that my PC is not getting ntp updates and therefore is running on CMOS clock alone, which is running a bit fast. I have discovered a command: 

C:\windows\system32> w32tm /resync
Sending resync command to local computer
The computer did not resync because no time data was available.

The more difficult question now is 'Why not?' I may be some time... 😣

[#6]

Try -

w32tm /resync /force

Also -

In Date & Time settings → Additional date, time & regional settings → Internet Time → check/change the server

try -

• time.windows.com
• uk.pool.ntp.org
• time.cloudflare.com

[#7]

@ExForce9 

Here is an example of a Hub two updating it's time using ntp.plus.net

16:48:01, 09 Aug. NTP synchronization success
16:48:01, 09 Aug. NTP Server: ntp.plus.net

nslookup ntp.plus.net
Server:  dns.google
Address:  2001:4860:4860::8888

Non-authoritative answer:
Name:    ntp.r53-gslb.vision.bt.com
Address:  213.123.16.85
Aliases:  ntp.plus.net
          ntp.vision.bt.com

The Hub Two does not provide a NTP service for devices on the LAN;  they would connect to an internet based time server. Unless the time setting has been changed in the control panel. I would expect Windows to be time.windows.com it makes updates using UDP port 123.

[#8]

Look in the PC Clock for the Adjust date / time function.

The NTP server can be set and tested from the Internet time options.

[#9]

@pvmb  has been gone for hours, considering they were only going to alter some NTP clock settings to realign time with British Summer Time.

Perhaps @pvmb accidentality re-activated H.G.Wells's "The Time Machine" and been transported to year 802,701 AD ?

I guess we'll just have to wait until @pvmb gets back from visiting the Eloi and Morlocks !.  

[#10]

@pvmb  What version of Windows are you using?

If W11 then open Settings > Time & language > Date & time. In additional settings click on the down arrow next to "Sync now". This will open the "Change the time server" box. Click on "Change". My server address is set to time.windows.com. That address is working fine for me.

[#11]

---

@pvmb wrote:

...Thanks for all the suggestions.

Looking into this, the simple answer is that my PC is not getting ntp updates and therefore is running on CMOS clock alone, which is running a bit fast. I have discovered a command: 😣

---

So did you investigate the suggestion from post #3? It would be most helpful in eliminating potential causes if you reported back.

You can tinker with Windows commands until the cows come home but if the Plusnet firewall is blocking access to ntp servers.....

[#12]

https://time.is/
Your clock is 5 minutes and 52.0 seconds ahead

C:\windows\system32> net start w32time
The Windows Time service is starting.
The Windows Time service was started successfully.

This command then demonstrates that my Windows PC cannot obtain a time update:

C:\windows\system32> w32tm /resync
Sending resync command to local computer
The computer did not resync because no time data was available.

But this command demonstrates it is, nevertheless, in contact with the time server pool.ntp.org and 352 seconds is out by 5 minutes 52 seconds.

C:\Windows\system32>w32tm /stripchart /computer:pool.ntp.org /dataonly
Tracking pool.ntp.org [162.159.200.1:123].
The current time is 09/08/2026 20:58:04.
20:58:04, -352.2424906s
20:58:06, -352.2415969s
20:58:08, -352.2415794s
20:58:10, -352.2413495s
20:58:12, -352.2407604s
20:58:14, -352.2418965s
20:58:16, -352.2408391s
20:58:18, -352.2412611s

Try turning the Plusnet Firewall OFF:

C:\Windows\system32>w32tm /resync
Sending resync command to local computer
The command completed successfully.

But have now lost my long term static IP address, turning PN Firewall on again ("Block common ports except HTTP and HTTPS") does not restore it!

[#13]

@pvmb 

You need to set the Firewall to LOW.

Not sure why you think you need the account firewall other than to maintain a static IP. Hopefully the Hub two firewall provides all the protection you require.

Edit: with the firewall on it is likely going to be a static IP address, but not the same one.

[#14]

@Dan_the_Van 

"You need to set the Firewall to LOW."

No, that doesn't work either:

C:\Windows\system32>w32tm /resync
Sending resync command to local computer
The computer did not resync because only stale time data was available.

A different message...

It seems the Plusnet Firewall needs to be OFF for the Windows timeserver updater to work. I used to have it set to "Block common ports except HTTP and HTTPS". That didn't work either. I assume it is blocking UDP on Port 123.

Interestingly, I now have no current reverse DNS. GRC | ShieldsUP! — Internet Vulnerability Profiling

[#15]

@pvmb 

I used the Firewall for years and never had any ntp issue, I was always set to LOW I've now turned if OFF as it's pointless as I have a static IP, for many years now, maybe more than 20.

I've always let the OS build decide on ntp choice, not really seen a reason not to.