I'm bumping this issue as I know threads already exists but this is a persistent problem and a massive time sink.
PLEASE: Cache the icons/thumbnails for ALL the enscape assets to a locally accessible file.
I am in China where download speeds from international servers are often poor. This renders the library virtually useless at times.
I am working in HBA doing hospitality interior design and am trying to make Enscape a part of our department's workflow. I just had an awkward moment trying to demonstrate the library to a small team of people. Please sort it out soon.