[German]Windows contains a feature that creates a backup copy of the registry files at regular intervals. In Windows 10, however, it looks as if this task fails in versions 1803 and 1809.
In Windows there is a folder C:\Windows\System32\config\RegBack in which the operating system can cyclically store copies of its registry files. There is a task in the branch Microsoft -> Windows -> Registry in the task planner for this purpose.
This task cyclically creates various files in the RegBack folder. I checked this under Windows 7 times in an administrative command prompt. This looks like this:
The system-wide valid structure files of the registry (hives) can be found. In SOFTWARE, for example, all installed programs can be found and under SYSTEM the registration keys for the system are stored.
You can also try to copy backed up hive files from RegBack back to Windows PE manually. This August 2018 post describes these steps to manually retrieve the whole thing. This forum post describes an [unsuccessful] attempt to write the files back manually (the copies were probably already damaged). And the whole thing wasn’t really reliable – at least in this 2017 HP forum article there is one whose RegBack folder was empty when he needed it. Whenever the trigger of the task planning fails, no backups of the hives are written.
Windows 10 V1803/1809 RegBack fails
In Windows 10 Version 1809 the registry backup task doesn’t work anymore. If you inspect the RegBack folder, you will see, it is empty, although there is a backup task.
Even a manual execution of the task to backup the registry hive files does not change this. I then searched the Internet – this forum entry in MS Answers from June 7, 2018 complains about this effect already on Windows 10 V1803. A user writes that the files would have a size of 0. Other users confirm these observations. It is assumed that Microsoft silently ‘killed’ the registry backup from Windows 10 V1803. In version 1809 the folder is even completely empty. This tweet also already discussed this observation for Windows 10 V1803, and some people try to bring it to the attention of the Microsoft developers in the feedback hub or via Twitter. #Windows10 1803+ no longer creates backup copies of the registry
#Windows10 1803+ no longer creates backup copies of the registry
Major blow to the Windows emergency restore abilities (forum support).
Plz RT & ? in #feedbackhub
— Vadim Sterkin (@vsterkin) 30. Oktober 2018
Seems that either this feature was deprecated, or a bug prevents the task from creating backups of the registry hives.