Since the update of MacOS Mojave from 10.14.3 to 10.14.4, webarchives are not displayed within Scrivener (see also [url]https://forum.literatureandlatte.com/t/problem-with-importing-websites-after-update-mac-os-mojave-10-14-4/45103/1]. That problem should be immediately resolved!
I’m not sure why we need a separate thread for this, especially since you already posted in one of the other two already existing threads. 