Microsoft Confirms Windows Update Problems Were Caused by DNS Issues

Since January 29th, Windows 10 users have been reporting problems connecting to Windows Update. Microsoft has confirmed that this was caused by DNS corruption at an external DNS provider that was causing bad records to be pushed to ISP's DNS servers.

Just yesterday we reported that even though Microsoft had reportedly fixed the issue, users were still complaining that they were unable to connect to Windows Update. At the time of that article's writing, Microsoft had still not disclosed any information regarding the cause of the problems.

As users were able to resolve the Windows Update problem by switching their DNS servers to Google's 8.8.8.8 service of Cloudflare's 1.1.1.1 service, we suspected that this was a DNS issue.

In a new update last night to the Windows 10 and Windows Server 2019 update history support article, Microsoft has confirmed that this problem was caused by data corruption at an external DNS service provider. This caused incorrect records to be pushed to downstream DNS servers at other ISPs.

"The Windows Update service was impacted by a data corruption issue in an external DNS service provider global outage on January 29, 2019. 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."

Microsoft has stated that the issue was resolved on January 29th, but some ISPs cache their DNS data for many days to increase performance. Due to this, the affected DNS providers kept serving the incorrect information even if the original DNS servers have been fixed to contain the correct information.

While there have been reports from users all over the world being affected by this DNS corruption, more complaints appear to have been coming from Comcast in the U.S.A. and BT customers in the UK.

If you are still having problems connecting to Windows Update via your normal Internet service provider's DNS servers and it works fine when using Google's or Cloudflare's DNS servers, then you are just going to have to wait for your ISP's DNS servers to pull down the correct DNS information again.

If your ISP is stating that everything is working properly now, then it is possible that you have the incorrect DNS record cached in Windows 10. To flush the DNS cache, you can follow these steps:

1. Right-click on the Windows Start button.
2. Select either Command Prompt (Admin) or Windows PowerShell (Admin).
3. When the window opens, type ipconfig /flushdns and press enter on your keyboard.
4. Windows should respond with "Successfully flushed the DNS Resolver Cache", which indicates that the cache was cleared.

Now that you have flushed the DNS cache, you can try to connect to Windows Update and see if it is working. If it is not, then you will have to switch to different DNS servers for the time being or wait for your ISP's servers get updated with the correct information.