That may be part of it… for modern games, Blizzard advises that games cannot be installed on external drives or network drives… something about Windows disconnecting from external drives… see https://us.forums.blizzard.com/en/blizzard/t/blizzardnet-desktop-app-not-downloading-any-games/14820/2.
Mine is installed on the C: drive… takes a bit less than 2 GBytes.
The game version is displayed on the main screen… see my screenshot here: https://i.imgur.com/8W1gW3d.jpg (copy link in your browser). If yours says 1.14B, it’s because you haven’t applied the last patch… the one that brings you from 1.14B to 1.14D; see my post https://us.forums.blizzard.com/en/blizzard/t/i-cant-install-d2-or-lod/20950/7 for some instructions on how to install that patch.
Is there a way to pause Windows defender while you install Diablo II ?
I hope this helps. Good luck !