You can add a new rule to SPF following the steps delineated here. The application is w32Time located under System32 is memory serves right.

However if SPF doesn't complain, the problem is certainly elsewhere. I see to remember having had problems with time sync before. I really can't remember what the reason was in end. But two things seem to nag me:

• The service was stopped or in Manual or something, and needed to be in Automatic(?).
• My router was blocking it

Errors coming from the time servers alone seem unlikely. As you say you have tried others. But in any case KB262680 contains huge lists of time servers you can use.

Meanhile KB314054 reveals manual configuration instructions of the service in the registry along with a detailed explanation of all keys further down the page. Could be a case of a bad registry configuration.

All the best.

I would highly suspect Ubuntu and Windows disagreeing on whether the hwclock is localtime or UTC. The conflict usually comes about because Linux uses the the hwclock set in UTC, while Windows uses the hwclock set to the localtime zone.

If you want your hwclock to show the time in your timezone, then you will need to change linux to not be UTC, which means make linux use localtime. If you are OK with your hwclock (BIOS) to be in UTC, then change windows to be UTC.

From here:

Make Windows use UTC

Note: This method was not initially supported on Windows Vista and Server 2008, but came back with Vista SP2, Windows 7, Server 2008 R2 and Windows 8/8.1.

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To make MS Windows calculate the time from the hardware clock as UTC.

Create a file named WindowsTimeFixUTC.reg with the following contents and then double click on it to merge the contents with the registry:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
 "RealTimeIsUniversal"=dword:00000001

Note: Windows Time service will still write local time to the RTC regardless of the registry setting above on shutdown, so it is handy to disable Windows Time service with this command (if time sync is still required while in Windows use any third-party time sync solution):

sc config w32time start= disabled

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Reversing the change.

You can create a file with the following contents and then double-click it to merge in the original changes, as above:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
    "RealTimeIsUniversal"=-

If Windows Time service was disabled, enable it again with the command:

sc config w32time start= demand

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Make Linux use 'Local' time

To tell your Ubuntu system that the hardware clock is set to 'local' time:

Pre-Ubuntu 15.04 systems (e.g. Ubuntu 14.04 LTS):

edit /etc/default/rcS and add or change the following section

#Set UTC=yes if your hardware clock is set to UTC (GMT)
UTC=no

Ubuntu 15.04 systems and above (e.g. Ubuntu 16.04 LTS): open a terminal and execute the following command:

timedatectl set-local-rtc 1