My experience attempting to update windows10
Last year I mistakenly recommended to my daughter to buy an inexpensive HP Stream 11 notebook for her first year of college. With all due respect, it has been a great machine but the insufficient storage is a negative. I was not aware that it did not have expandable storage (the eMMC hard drive is embedded on the motherboard and a technology I haven't seen before). When I tried to upgrade her machine from windows 8.1 to windows 10 I had to jump through multiple hoops in order to get the upgrade to happen due to insufficient storage (ie: removing the 8.1 preventing downgrade, removing unused applications and using an external hard drive). Flash forward a few months and there was an update to version 1511 but nothing I tried allowed the update to progress due to a bug with the update not handling external drives properly. No matter how large the drive I had attached was, I got an insufficient disk space message. I discovered a few KB articles that addresses that particular issue