Peter Jason wrote:
Win7 pro SP1

I am trying to install Win10 from the ISO disk of August15, on top of
my existing system, but the upgrade seems to have stalled on the
"Getting Updates", "Checking for updates" window, with the little
balls going round & round & round & round...
So far this has been going on for 20 minutes; should I backstep and
skip this "get Updates" option?
Peter

The advice from the Win10 newsgroup is to let it run.
24 hours is not unreasonable.