If you’re running Windows 10 today, and you’re on version 1803, I implore you to go into Settings > Updates and security > Updates and turn off the automatic upgrade by deferring feature updates for either seven days, or up to 14 days if you’re on Windows 10 Pro. If you can’t do either one, do whatever else it takes to stop the update from being deployed to your system: set your network connection to a metered connection, disable the update service, or run ShutUp10 to halt them. The reason why I give this advice is because there’s a significant chance that the upgrade to Windows 10 1809 will nuke your personal files because it is affected by a bug, and those files have a significant chance of being unrecoverable. If you’re still going to go ahead with the upgrade, backup all your data beforehand. See this Reddit thread for more details. There’s several other bugs being thrown in with this build, from incorrect CPU usage reports to stuttering with the Edge browser, so avoid it if at all possible for the next two weeks.