https://www.techradar.com/news/microsoft-has-fixed-that-file-deleting-bug-in-the-windows-10-october-2018-update

After having to embarrassingly halt the rollout of its big new October 2018 Update for Windows 10 late last week – just days after its original release – Microsoft has today said that it’s squashed the file-deleting bug that was the cause for the pause, and is preparing to redeploy the update pending testing by Windows Insiders.

Under specific conditions, the bug resulted in the deletion of predefined user folders, such as Documents and Pictures, when a feature called Known Folder Redirection (KFR) was also in use. KFR allows users to change the location of those predefined Windows folders – so they can be moved to other drives, for example – but to be affected by the bug, users also needed to have kept the original (old) versions of these predefined files and folders in place.