If you installed the new Windows 10 version Anniversary Update πάνω από μια προηγούμενη έκδοση των Windows, θα παρατηρήσατε ότι ο ελεύθερος χώρος στο δίσκο σας μειώθηκε σημαντικά.
Με την αναβάθμιση από προηγούμενη έκδοση των Windows, το Windows 10 αποθηκεύει πολλά αρχεία από την προηγούμενη έκδοση κατά τη duration of the upgrade, and thus your hard drive is filled with files that you may not need again, especially if your upgrade was successful. 
Setup saves these files, just in case something goes wrong with your OS upgrade. If something goes wrong you can reset me better safety the previous version of Windows.
But if everything works perfectly, there is no reason to keep garbage on your computer.
Below we will see how you can free up space after upgrading your operating system (Winaero):
Press them together two Win+R keys to open the Run dialog.
Type the command and press Enter:
cleanmgr
Select the drive that is installed in your operating system (usually in C) and press OK.
Click the Clean up button to enable the Disk Cleanup tool.
Find and select the files of your previous Windows installation (s).
Click OK and you're ready.
