As per Microsoft windows blog, Last week Microsoft has paused the roll-out of the Windows 10 October 2018 Update (version 1809) for all users when users reported missing files after applying the October update. Now Microsoft is re-releasing October update.

Updated version of Windows 10 October 2018 Update released to Windows Insiders

“Prior to re-releasing the October 2018 Update our engineering investigation determined that a very small number of users lost files during the October 2018 Update. This occurred if Known Folder Redirection (KFR) had been previously enabled, but files remain in the original “old” folder location vs being moved to the new, redirected location. KFR is the process of redirecting the known folders of Windows including Desktop, Documents, Pictures, Screenshots, Videos, Camera Roll, etc. from the default folder location, c:\users\username\<folder name>, to a new folder location. In previous feedback from the Windows 10 April 2018 Update, users with KFR reported an extra, empty copy of Known Folders on their device. Based on feedback from users, we introduced code in the October 2018 Update to remove these empty, duplicate known folders. That change, combined with another change to the update construction sequence, resulted in the deletion of the original “old” folder locations and their content, leaving only the new “active” folder intact. Accordingly, below are the issues we have identified and fixed:”