The factors that impact the amount of free hard drive space needed to take an update include: the versions of Windows previously installed on the machine, the amount of disk space available to reuse from Windows files, such as the virtual memory pagefile or hibernation file, which applications are installed on your device and how those applications store data.
The size of the Windows operating system that comes with your device and the amount of space needed to download and install Windows updates, are highly variable as they depend on a variety of factors.
