Microsoft has now confirmed that the cause of last week's Windows Update failure was a global outage at an unnamed external DNS service provider on January 29.
That outage left some Windows users in the US and UK unable to get security, software, and operating system updates from Microsoft's update service.
The issue affected Microsoft's update service for Windows users in the US on Comcast, as well as UK customers on BT Broadband. Some users were able to get updates working by changing their computer's DNS settings to Google's Public DNS.
Microsoft's explanation fills in some gaps about why users couldn't connect to Windows Update for several days after January 29.
Microsoft on late Monday said although the outage at an external DNS provider was fixed on the same day it occurred, "a few customers" continued to struggle to connect to Windows Update. The delay is because it takes a while for other downstream DNS servers to be updated with the corrected DNS entries for Windows Update.
"The Windows Update service was impacted by a data corruption issue in an external DNS service provider global outage on January 29, 2019," said Microsoft.
"The issue was resolved on the same day and Windows Update is now operating normally, but a few customers have continued to report issues connecting to the Windows Update service. We expect these issues will go away as downstream DNS servers are updated with the corrected Windows Update DNS entries."
SEE: 20 pro tips to make Windows 10 work the way you want (free PDF)
That would help explain why users on BT's forum continued reporting problems connecting to Windows Update over the weekend, while Comcast users reported the issue being resolved by Friday. Some customers at British ISP TalkTalk also reported problems connecting to Windows Update.
Microsoft is relying on Windows Update to resolve a long-running block on some Intel display drivers. That block was first imposed in November, shortly after Microsoft resumed the Windows 10 1809 update after suspending it due to a data-destroying bug.
The buggy drivers broke audio playback from monitors connected to a PC. Microsoft says Intel has now released updated drivers to PC OEMs, but these OEMs must make the new drivers available through Windows Update.
Windows 10 updates are broken again, but this time it's not Microsoft's fault
Windows 10 users switch to Google's Public DNS after bad ISP DNS setting blocks Windows Update.
Microsoft cloud services see global authentication outage
Office 365, Dynamics 365, Azure Government Cloud impacted by authentication issue.
Windows 10 19H1: We'll fix confusing setup error messages, promises Microsoft
Would the average Windows user know what a KB is or what to do with one?
Windows 7 versus Windows 10: Here comes the final showdown
With less than a year to a major Windows 7 support deadline, it's decision time for the PC.
Windows 10 19H1: Microsoft pushes its services with 'Make Windows even better' prompt
Microsoft wants you to "make Windows even better" by setting up Microsoft Account services on Windows 10 devices.
Microsoft's new Windows 10 19H1 test build is taxiing toward the finish line
Microsoft's latest Windows 10 19H1 (1903) test build is light on new features, and heavy on fixes -- which is expected as it rolls toward completion.
How to turn features on and off in Microsoft Windows 10 from the Control Panel TechRepublic
Microsoft decided to conceal the traditional Control Panel, but you can still access it if you know how.
CES 2019: Everything we saw, from 8K TVs to amazing fake burgers CNET
The show opened with a bombshell from Apple, closed with a surprise from Samsung and had plenty of news in between.