i cant seem to free up space

having run WinDirStat it doesnt show me much usage.

Onedrive is trying to sync, and despite saying that i want to view files online i think the space is not being freed up. when i click on a file it says the full size and then the size on disk (a few k) but i dont believe it.

Anyone have any ideas? It has used all 32 gig and i only have 2 meg left!