At problems when auto upgrading to Windows 10, from Windows 7 or Windows 8.1 and 8.
Here on the MS page you will find some useful tips and the error messages when you upgrade to Windows 10:
But in most cases, it is so that the installed apps and software, make the free auto upgrade to Windows 10, impossible and this causes error messages.
You must then make an upgrade to Windows 10 without the installed software and APPs.
Change what to keep at upgrade to Windows 10! (... see Image-1 Arrow-1)
Keep Personal Files only (... see Image-2 Arrow 1 and 2)
See also: Upgrade Windows 7 or 8.1 to Windows 10, anything else I should know || Windows 10 no Product Key
FAQ 131: Updated on: October 15th 2015 13:51