I have Lightroom 6.6 (not CC).
I recently got a new laptop, HP Zbook G3, Win 10 64-bit pre-installed.
I installed Lghtroom, including the last update, then I opened my catalog. All thumbnails are shown black, with a sort of posterized effect (see screenshot)
Tried the solution from this post Thumbnails are black in Lightroom CC 2015.2/6.2 , totally useless.
Tried discarding a recreating all previews, useless too.
Right now Lightroom is totally useless, all I see are black squares, even if I open the single image.
All image files are not corrupted and show up correctly in File Explorer.