While you may want to get the latest features in the Windows 10 October 2018 Update as soon as possible, make sure that you back up your files first. Some users are reporting that the update is causing files in the user directory to be deleted, including documents, photos and music. MSPoweruser first reported the news.
Several users and reports are suggesting that the issue has something to do with OneDrive. Some users suggest that folders and documents backed up to OneDrive are the ones most likely to make it through the update.
Tom's Hardware has reached out to Microsoft and will update if we hear back.
Additionally, ZDNet reports that some devices may see issues with certain Intel audio drivers (intcdaud.sys, versions 10.25.0.3 – 10.25.0.8) that "may result in excessive processor demand and reduced battery life," according to a Windows support document. Those users will be blocked from updating, though some may see a warning message. Those users affected should hit the back button and stay on the current version of Windows 10.
Intel says a fix for the audio driver problem is available in version 10.25.0.10, which is included with Intel Graphics Driver version 188.8.131.5286. Intel suggests that all users with 6th Gen or newer processors update to that graphics driver before updating.