Microsoft leaks cause of Windows 10 October Update File Deletion bug

A week ago Microsoft posted a two thousand word self-congratulatory blog post on how each bi-yearly Windows Update was better than the last, with happier users and fewer issues each time.

This is despite users becoming increasingly wary of updating their PCs with more and more reports of serious and crippling bugs end users are often left to deal with.

The blog post was exactly the opposite of what users were expecting – an explanation of what happened and of how Microsoft would prevent it from happening again.

It seems Microsoft decided instead to leak the information to a fan site – Windows Central, who explains the issue:

After Microsoft pulled the October 2018 Update, it became apparent that Windows Insiders had reported the very same issue in the Feedback Hub months before the October Update was finalized. At that point, many started to wonder how and why this feedback was seemingly ignored or unseen by Microsoft. According to people familiar with the matter, engineers at Microsoft did, in fact, see the reports from Insiders about losing their files after an upgrade. But they mistook those reports for another issue that wasn’t as severe as the actual bug turned out to be. In other words, Insiders were reporting losses of files related to two different bugs, one of which was no severe and wasn’t actually deleting any files at all.

I’m told that during the last two years, Microsoft has received a very, small number of reports in the Feedback Hub every month along the lines of “My files have been deleted after installing the latest build or update.” When Microsoft looked into these issues originally, it found that some users were being booted into a temporary account upon installing new builds. Those users were mistaking this temporary account as their own, and when accessing the documents folder they saw that all their files were gone. In reality, all their files were exactly where they left them in their account, and they were just not logged into their account to see them. As a result, Microsoft at some point added a popup in the temporary account that explains to the user that they have been booted into a different profile and provides support for how to get out of that state.

This is why Microsoft seemingly dismissed the reports from Insiders that actually had their files deleted after installing the October Update. Engineers assumed those reports were related to the temporary account issue, which had already been addressed.

Those that really were suffering from deleted files reported the exact same symptoms in the Feedback Hub. They didn’t know what the cause of the issue was, so they merely stated that their files had been deleted. Known Folder Redirection was the culprit, but Insiders didn’t know that at first. Long story short, Microsoft had mistaken one bug for another, so it did not address the new reports right away.

The WC reports that Microsoft had a “huge wakeup call” and was trying to improve systems to make sure the same issue does not happen again, and in particular have added a severity rating system for feedback.

While we now know what happened, it is notable that there was a second file deletion issue in the same October 2018 update, and  I have not heard a convincing explanation of the process changes Microsoft would make to make sure such issues do not hit the public. It is also interesting that Microsoft has not made any official public autopsy of the root cause of the issues which led to October 2018 Update shipping with such a serious bug.

Are our readers satisfied with the explanation, and the fact that it has not come via an official source? Let us know below.