Reason Behind Users Files Deletion Bug in Windows 10 October 2018 Update
SUMMARY: Microsoft has found out the reason behind automatic file deletion bug in Windows 10 October 2018 feature update (version 1809). The company has fixed the issue and re-released the new feature update to Windows Insiders group for testing and feedback. In coming days, Microsoft will re-release the new updated feature update to public.
When Microsoft released the new October 2018 feature update for Windows 10 operating system to public, lots of people faced major bugs and issues. The biggest bug and issue was the automatic deletion of users personal files and data present in user profile folders such as documents, downloads, pictures, music, videos, etc.
Windows 10 October 2018 update automatically deleted files and folders present under user profile folder for several users when they upgraded previous Windows 10 versions to the new feature update version. Many users reported that the new feature update removed the whole user profile folder.
When several users reported this bug, Microsoft acknowledged the critical issue and paused the distribution of Windows 10 October 2018 update. Microsoft pulled the feature update from Windows Update. The company also removed the offline ISO files and other media from its servers.
Microsoft started investigating the file deletion issue and today in an official post, the company revealed the reason behind this weird and serious issue.
Previously people were claiming that the issue was caused by a group policy "Delete user profiles older than a specified number of days on system restart" enabled under "Computer Configuration -> Administrative Templates -> System -> User Profiles" section in Group Policy Editor (gpedit.msc).
According to Microsoft investigation report, the file deletion bug was caused by a built-in feature called KFR (Known Folder Redirection) in Windows. If a Windows 10 user used the KFR feature in past, he might have faced the file deletion issue.
Now you might be wondering what is this KFR feature? Here is the description of this feature:
KFR (Known Folder Redirection) is a feature present in Windows operating system which helps users in changing the location of personal folders such as Desktop, Documents, Downloads, Pictures, Music, Videos, Screenshots, Camera Roll, etc present under user profile folder. Using this feature, you can move the default user profile folders from "C:Usersusername" location to a new location.
Many users use this feature. For example, if you save or store lots of data such as movies, videos, songs, photos, downloaded files, etc in your user profile folder, you might be worried that if you format C: drive to install a fresh/clean Windows version, you'll lose all your important data. In such case, users take help of KFR feature to change location of these default built-in folders. They move these folders to a different drive such as D:, E:, etc. Once they change locations of these folders, they can format C: drive without worries in future and their data will remain safe on other drives.
Similarly, many people change these default folders location due to low disk space issues. If their C: drive size is small, they move these user profile folders to other drives, so that they can store as much data as they want in these folders.
Now you may ask how is it done? Here is the answer:
To change location of a personal folder present under user profile folder, right-click on the desired folder such as Downloads and select Properties option. It'll open folder properties window. Now go to "Location" tab. Here you can change location of the folder. Click on "Move" button to select a desired folder which will be set as the new location of the folder.
When you select the new location and click on Apply button, Windows asks you to move all the existing files present under the current default folder to the new selected folder. Windows shows a confirmation dialog box containing a message "Do you want to move all of the files from the old location to the new location? We recommend moving all of the files so that programs needing to access the folder's content can do so". If you click on Yes button, all files/folders are moved to new location. If you click on No button, existing files/folders are remained in old location.
To restore default location of the folder, you can click on "Restore Default" button.
Now you must have a good idea about this KFR feature. Let's talk about the file deletion bug reason!
The file deletion bug occurred if a Windows 10 user used the KFR feature to change location of personal folders but he clicked on No button when Windows 10 asked the user to move existing files to new location. In other words, the user changed location of personal folder but he kept existing files in old location.
Windows 10 October 2018 update was designed to automatically remove the empty and duplicate known folders as many users provided this feedback to Microsoft. Microsoft implemented this code in October 2018 update. If a user changed location of user profile folders, the October 2018 update deleted the old folder as it was a duplicate of new folder.
According to Microsoft, the issue also occurred to users who configured the known user profile folders to be redirected to another folder on OneDrive or users used an early version of the OneDrive client and used the OneDrive settings to turn on the Auto save feature.
In all the above mentioned cases, default personal folders present inside user profile folders were changed/moved to a new location but some data was left in previous/old location. Since October 2018 update was designed to delete old duplicate known folders, it automatically deleted those old known folders and the data inside those folders was also removed.
So that's the reason behind automatic files/folders deletion bug in Windows 10 October 2018 feature update.
So did Microsoft fix the issue?
Yes! Microsoft has fixed the issue and implemented solutions in the October 2018 update. Now the original or old folder content remain intact even if you moved the folder and didn't move the files/folders inside it.
Currently Microsoft has re-released the updated Windows 10 October 2018 update build to Windows Insiders. Microsoft will monitor all feedback and reports and if everything goes fine, the company will re-release the October 2018 feature update to public.
So wait for some days and we'll inform you as soon as the new updated October 2018 update becomes available again for Windows 10.
PS: If you already installed/upgraded Windows 10 October 2018 feature update in your machine when it was initially released on October 2nd, 2018, you should immediately check for new updates on Windows Update. Microsoft has released a new update "KB4464330" for October 2018 update which fixes the automatic file deletion bug.