Hi,
another problem: Avast prohibits Adobe Lightroom installation. Came from someone at a photographer’s forum.
Message was “eine Bedrohung wurde erkannt und der Vorgang gestoppt”.
He deinstalled Avast, and the update worked …
Just a notice from me 
You/He can report a suspected FP here: https://www.avast.com/false-positive-file-form.php
I gave him this link.