Some fresh intelligence on how Windows 10 installs are completed is now with us, and it seems that Microsoft has added new features that enable easier installation of its upcoming operating system.
Added them quietly, but this is now the modus operandi for the company.
Stealth.
Anyway, with Windows 10 tracking for launch on July 29, this new addition is bound to come handy for users that install the OS on devices with limited storage — as reported, new options are provided when initiating the Windows 10 upgrade on a computer that does not have enough space.
These new options help to successfully deploy it, without the need to remove any files.
For starters, Microsoft tells you that “Windows needs more space”, displaying the amount of space needed to complete the installation. But then says:
“To make more space available for the upgrade, remove any files and apps that you no longer need or try one of these options: use Disk Cleanup to free up space or choose another drive or attach an external drive with available space.”
Elaborate.

The official
Windows 10 system requirements published by Redmond list 16GB of storage space for the base 32-bit version of the operating system, while 20GB for the more popular 64-bit flavor.
But just in case you are strapped for space, then an external drive can also do the job.
Ingenious.
source:windows10update