Microsoft is gradually moving all of Window 10’s native setting UI from WPF (Windows Presentation Foundation) to UWP (Universal Windows Platform). This is in line with what Microsoft has been pushing towards since the introduction of Windows 10. The latest change comes to a new way to clean up your primary OS partition, aka usually would be your C drive. Gone are the old days right-click on the C:\ drive and go to Properties > Disk Cleanup for C:\, in is the new UWP user interface integrated inside the Settings app.
As of Windows 10 Preview build 17074, Microsoft added Disk Cleanup inside the System > Storage area.
If you have a new Windows 10 build, go to Settings > System > Storage. Under Storage sense, there is a new link named “Free up space now” that will take you to the new page that shows what “Disk Cleanup” used to show.
By default, remove “Previews Windows installations(s)” is not selected. The list for “Free up space now” also grows dynamically and it now only shows the items that are relevant. Unlike the previous version of Windows, Disk Cleanup tool would always show all options with empty checkboxes regardless if there are any files stored under a given category.
Next time when you have a new Windows 10 installed or upgraded, be sure to look out for the new settings for disk clean-up. Yes, the old method of accessing Disk Cleanup tool via the traditional right-click of a given hard drive via Properties still exists but sooner or later Microsoft will have a complete overhaul of UWP to replace the legacy WPF UI.