After working on a machine that through up the “Something happened” error trying to upgrade to Windows 10 – I used the iso image approach to burn a disk. In this case it was able to shine a light on the essence of the problem. The issue for me was Sophos Antivirus. When the ISO version set up ran it was able to tell me that the app needed to be removed – but when I ran it through it came back with “insufficient rights”. I manually removed Sophos and the install completed.
So if you are getting the “Something Happened” message and have access to an iso buring app – worth giving that a spin to see if it tells you more about the nature of the problem.
Postscript – bear in mind that if you use the ISO image to install you will require a Windows 10 activation key – so only use this route to install if you have one.