I just helped a work colleague set up their new Cloudbook, which is basically a just a fancy new name for 'Netbook'.
With the laptop new out of the box, it had just about 4.5GB used on its tiny 32GB SSD. I didn't realise Windows 8.1 x64 could take up this little space considering this also included a hibernation file and a 512MB page file. Despite being a Lenovo brand computer, it surprisingly had just its 'Lenovo Solutions' package pre-installed, no pesky McAfee/Norton installation (or icon) or other bloatware that I noticed.
However, that minimal space usage didn't last very long. Within minutes, Windows presented a Windows 10 upgrade screen, which I proceeded with and then this appeared:
Whoops! I had a blank 16GB USB stick handy, so chose that option. It then said 'Preparing for installation' and got stuck at about 80%. I brought up the task manager and it showed no CPU usage, disk or network activity. I left it for another hour, but nothing happened, so I decided to try restarting the laptop. It then said "Installing update 1 of 1" and got stuck there with no sign of activity. After another 15 minutes, I forced powered it off, which was not easy with the laptop constantly going in and out of sleep each time I pressed the power button and a non-removable battery.
Once booted, it brought up that same Windows 10 upgrade screen and this time it appeared busy with steady activity for about 2 hours. Once it "completed", the laptop rebooted and up came Windows 8.1 again and then said "Updates were installed". Going by its updates history, it installed something like 100 updates with the final one "Windows 10 version 1511" showing 'Failed'. At this stage, the disk usage grew to something like 16GB and I thought there's no way it's going to install Windows 10.
Anyway, up came a screen saying Windows updates are ready to install and sure enough it's the Windows 10 installation. During my last hour at work, it was still going through the 'Preparation for installation' stage with steady CPU and disk activity, so I configured its power settings not to sleep and asked my manager to check the laptop before he headed off in case it asked anything else.
On Monday morning, he said it did bring a message asking to accept the agreement (that stupid message it should be asking at the very start) and was at 1% when he closed the place an hour later. When I checked in this Monday morning, it was finally running Windows 10. I then tried seeing what space I could free with this trick:
First thing that's obvious is the "18GB recoverable space" is more than the actual used capacity on the SSD! So I went ahead anyway and the following is what it brought the usage down to:
Basically what seems to have happened is that it just deleted the contents it had on the USB stick, plus a few GB it had in the windows.old folder on the SSD.
Once I installed the remaining Windows updates for Windows 10 along with LibreOffice, Avast and Chrome, its disk usage grew to 15.6GB with just 12.6GB free. Not a lot of free space for a brand new laptop, but worth noting for anyone considering getting a Cloudbook or a Windows tablet that comes with just 32GB of storage capacity.