When you want to find out where the disk space disappeared on your computer, you can use disk space analyzers.
One of the best disk space analyzers is Windows Directory statistics. The analyzer will provide you visual and tree structure for the largest files and folders. So you can easily orient yourself.
Once you open WinDirStat, you will need to choose which partition and / or hard drive to scan. Depending on the size of your hard disc, the number of files and performance of your computer, it might take about 5 minutes (or more). It is recommended for a faster scan to close all other programs. When the scan end you will have a similar screen.
Before deleting a file or folder, search the file or folder name in Google, do not delete system files such as hiberfil.sys and pagefile.sys.
Please, be careful what you delete and if you are not sure do not delete anything.
There are many disk space analyzers for Windows 10, WinDirStat is one of the easiest and most intuitive for use.