Windows 10: Cannot upgrade from Win 7 to Win 10 - "unknown error"

I am trying to upgrade from Win 7 to Win 10. Before proceeding I installed all the required Win 7 updates, then attempted to install Win 10. However every time I try I get:
"Code 80070780 Windows Update encountered an unknown error."
See attached screen captures.
"Get help with this error" is not helpful. I've clicked "Try again" 4 times now, always the same problem.
Any ideas?

:)

 

Win 7 Pro SP1 restore

Is Win 10 a "permanent" upgrade or can Win 7 be restored if Win 10 is not acceptable? And, if Win 7 cannot be restored, can Win 10 be installed on a 2nd bootable drive so Win 7 would not be lost?

 

Why does Windows 10 fail to upgrade my Win 7 Home Premium install on my HP G62?

The Win 10 upgrade has failed twice now, despite having all the necessary hardware requirements and free hard disk space. The install reverts back to the Win 7 home premium with an "unknown error" given as cause for install failure. What is the cause
of this? What can I do to fix it?

 

80070780 is a rather generalised File system Error - this would suggest to me that the actual install media downloaded for the upgrade has been corrupted

It's possible to download a new copy from Microsoft and use this to either Upgrade or Clean install

The Upgrade details are here ...

Windows 10 - Upgrade Installation - Windows 10 Forums

and the actual download is here ...

Windows 10 ISO Download - Windows 10 Forums

 

I downloaded the ISO file and burned to a DVD, then ran the setup. All seemed to progressing until I got the attached popup.