You may receive a Windows Error Code 0x80070643 while installing certain applications on Windows. Some users face this error while installing Windows Live Essentials like Windows Live Mail, Microsoft Security Essentials or even .NET Framework. This post will show you how you can try and fix this Windows error.
If while installing Windows Live Essentials, at the end of the installation you may receive an error message: These programs could not be installed.

0x80070643 – These programs couldn’t be installed
I suggest you try the following steps to redress the issue:
Uninstall the current version of your Windows Essentials software and use your junk registry cleaner like say, CCleaner to clear residual registry entries. Try to install it again using the Installer, this time. If you find that your green animation bar progresses up to a certain stage and then again reverses back, it means that the installation has again failed.
You may or may not get an Error Code 0x80070643 at the end. This may occur when the installers has insufficient privileges to modify a file or a folder.
To resolve this issue, Open Explorer and through Organize > Folder Options > View > Choose to show hidden and system files & folders.
Next navigate to C:\ProgramData\Microsoft\IdentityCRL and take ownership of this folder. You can add this command easily using our Ultimate Windows Tweaker.
Try again now. It should work!
If you receive this error while trying to install Microsoft Security Essentials, download and run this Microsoft Security Essentials Removal Tool to clear its remnants. Next, open Services Manager or services.msc and ensure that the Windows Installer service is running. Make sure your .NET Framework is up-to-date and try again.
If you receive this error while trying to install or update your .NET Framework, use this Fix It KB976982 released by Microsoft to resolve this issue.
I hope something helps!
