Microsoft has released update KB3122947 for Windows 10 Version 1511 a few hours ago. It seems that only a few users receiving this update and also a minority are facing install error 0x80070643. Here a few information about this update.
According the Microsoft’s KB-Article KB3122947 Update Some settings aren’t retained when users upgrade to Windows 10 Version 1511 from an earlier Windows 10 version has been undertook a revision to version 2.0 today (12/05/2015). The purpose of this update:
After an upgrade to Windows 10 Version 1511 from an earlier version of Windows 10, a very small number of users may have had their settings for Advertising ID, Background Apps, SmartScreen Filter, and Sync with Devices incorrectly set to the system defaults.
For more information about this issue, see Microsoft Knowledge Base article 3121244.
The update is only offered on machines that has been updated from Windows 10 RTM (build 10240) to TH2 (build 10586), and probably only, if update KB3121244 failed. According to Microsoft, the new update doesn’t replace another update.
Install fails with error 0x80070643
Some users are reporting (here and here) an install error 0x80070643 during updating a machine. This happens only after upgrade from Windows 10 RTM (Build 10240) to Version 1511 (Build 10586), if the user has deleted folder Windows.old. If that error occurs, there is a simple fix.
1. Press Windows+X and launch an administrative command prompt.
2. Enter the command given below and press Enter
dism /online /add-package /packagepath:C:\Windows\SoftwareDistribution\Download\
The command forces an install of the package already downloaded via Windows Update. How Windows Update history may be cleaned has been described here at MS Answers.