OK, I actually meant the large grey block at top center. The image showed that as a single block, not a whole bunch of tiny grey blocks.
The reason I'm asking you to check these is to discover where those files ar and what they might be.
At top center of the bottom window, that grey batch of tiny files...where are they? That looks to be maybe 15GB consumed space.
Bottom line - Its not a broken drive, or 'missing drive space'.
There just a bunch of stuff you've not yet discovered what and where it is.