@bob3160
Was “the iso file of the current Windows 10 1809 system” downloaded from here https://www.microsoft.com/en-us/software-download/windows10?
I don’t know what an ‘iso’ file is anyway. Whatever type of file mine was (if did did in fact even complete the download) it did not upgrade me from 1803–I have just rechecked with ‘winver’.
Re the point I made about ‘shadowfiles’, am I right in assuming that these would disappear with the removal/deletion of old Sys Restore points? That would be good if all traces of my attempt are gone.
The Microsoft site gives you 2 options. The first one is to install the upgrade now.
The second is to create Installation Media. That media is an iso file which can then be burned to a usb or a dvd. Here’s the info on an iso file, https://www.howtogeek.com/356714/what-is-an-iso-file-and-how-do-i-open-one/