The KB4048955 update for Windows 10 introduced some quality improvements and other elements that claimed to resolve security vulnerabilities. However, a bug caused error 0x80070643 to pop up every time the users tried to install the update. Error 0x80070643 is a general Windows Update installation error code that can appear on your computer screen during installation.
Windows Update error 0x80070643
Here’s what you can do to fix the issue.
1] Rename the SoftwareDistribution folder
Error 0x80070643 can either stop you from installing Windows update or installing another software. This issue may occur either due to the corruption of the MSI software update registration or if the .NET Framework installation on the computer has become corrupted.
To solve this, it is advisable to rename the SoftwareDistribution folder. To rename the Software Distribution folder, open an elevated command prompt windows, type the following commands one after the other, and hit Enter:
net stop wuauserv
net stop bits
rename c:\windows\SoftwareDistribution SoftwareDistribution.bak
net start wuauserv
net start bits
Next clear the contents of the Catroot2 folder.
2] Clear Catroot2 folder contents
Catroot and Catroot2 are the some of the important Windows OS folders which are required while Windows Updates process. So, if you are facing the problem while updating your Windows and receiving error message – 0x80070643, then reset the Catroot2 folder.
To reset the catroot2 folder do this:
Open an elevated Command Prompt, type the following command one after the other and hit Enter:
net stop cryptsvc
xcopy %systemroot%\system32\catroot2 %systemroot%\system32\catroot2.old /s
Next, delete all the contents of the catroot2 folder.
Having done this, in the CMD windows, type the following and hit Enter:
net start cryptsvc
Your catroot folder will be reset, once you start Windows Update again.
3] Run Windows Update Troubleshooter
Occasionally, when Windows users try to install the latest updates from Windows Update, they sometimes receive an error message – 0x80070643. The Windows Update Troubleshooter resolves many of these errors so run it and see.
4] Install Windows Updates in Clean Boot State
It is a good idea to install Windows Updates in Clean Boot State, since all non-Microsoft processes & Services do no start in that state and so there can be no 3rd-party interferences causing Windows Update to fail.
All the best!