Soon after Microsoft upgraded Windows October 10, 2018 to download a few days ago, users quickly discovered an annoying error: the upgrade ended with deleting user data on some systems. Microsoft stopped the release of version 1809 to investigate the case and found a solution. That means you will be able to upgrade to Windows on October 10, 2018, without fear of data loss.
Microsoft said in a new blog post that software upgrade was available to anyone who wanted it, by looking for updates. The company says that the number of customers who got 1809 was limited. Nevertheless, the loss of data was severe to those affected:
In just two days in rollout when we stopped, the number of customers who took the update in October 2018 was limited. Although reports of the actual data loss are few (one hundred percent of the version 1809 installed), there is any loss of data.
Microsoft says that the new Windows 10 version is currently available for Windows Insiders, with a wide rollout to follow, provided there will be no issues with the new version.
The company determined that the data gap problem lies in an error related to the KFR feature known mapping. If KFR was previously enabled, intentionally or incorrectly / automatically, but the files were left in the old location instead of being moved to the redirected location, they were deleted. This is because Microsoft tried to fix a previous KFR issue from the April 2018 upgrade, where KFR would create duplicate but empty known directories.
Microsoft explains that it has identified and determined different scenarios where KFR files were deleted so you should no longer encounter the problem. The company will help users who have lost data after upgrading to the October 2018 issue, although it can not guarantee recovery of lost data – check this page for more information on getting help.
If you are a Windows Insider, you can upgrade to version 1809 right now. Everyone else will have to wait a while longer. While waiting, consider backing up your data.