Thanks for your reaction and sorry for my late reply.
Then there's the Preference settings you have . . .
The above choices are set in a manner just to illustrate an issue which might be relevant to this post.
These ar my preferences;
I also noticed that LR is making a backup, so I assume that LR makes my originals bigger and also makes copy's of them. The original pictures on my external cource are 32GB, Lightroom Catalog Previews is 72GB!.
And then there's the Smart Previews . . .
But this is only helpful when you change images, or?
Could we have a little insight into perhaps your Prefs choices?