If you are a .NET developer and you need to clean up free space on your hard drive then you can get 10-15 GB by uninstalling old versions of the .NET core framework.
Apparently, every version of .NET Core and every update takes about 500 MB of your hard drive space. So all old versions combined may occupy 15 GB easily.
If you have not bound your project to a specific version then you need the latest version of .NET Core SDK only. All others waste your disk space.
To clean your hard drive, do the following:
P.S.: you may always just re-install specific .NET Core version on your machine again if you need it from this page