Windows partition suddently is full

[Maverick326]

Hi forum. Recently I have encountered this weird problem with Windows 10. The C: partition is absolutely full for no reason, not even a single byte left.The thing is that in reality its not even halfway full. What is it that I can do?
Thanks in advance.

 

[Alabalcho]

First, use Disk Cleanup app to free up some space, then install a utility like WinDirStat. Run it as administrator, and see where your diskpace has gone.