Windows Server 2016 Auto installs updates and restarts every month since 27th Nov 2019

[DST1]

I have checked the GPO that Windows updates are disabled and confirmed using regedit that the policy has applied but every month windows updates are installed and the 2016 server restarts.  As this only started in November last year is there a know bug that was introduced in the November Windows 2016 updates ?   The same GPO applies to 2012 R2 server and 2019 server and they have no issue it's only 2016 .

[DST1]

Thanks for the responses.  I know the GPO settings are correct because the policy works on 2012R2, 2019 and I can see the policy settings in the registry.  Just thought I would ask about updates/changes as the 27th on November 2019 was exactly when this started according to the logs so I thought I may have missed a KB article or some feature change.

[JanoschUlmer · Accepted solution]

There are many different Windows Update policies, would be great if you could be specific on what policies you set - some reference is available here: https://docs.microsoft.com/en-us/windows-server/administration/windows-server-update-services/deploy/4-configure-group-policy-settings-for-automatic-updates

If then the specific install of Windows Server doe snot act like documented, I would advise to open a support ticket on this. Checking in the support KBs i did no find a known issue for this. 

Also - the Tech Communities usually have an higher number of users specifically looking for certain technologies which might not be present in the Partner Communities: https://techcommunity.microsoft.com/ 

[DSPatrick]

I think windows is going to install critical updates regardless unless you disabled the wuauserv service. If you wanted more control over updating you could stand up a WSUS for the site then you'll have complete control over what updates are applied to the organization.