Microsoft has made it impossible to manually install the latest Windows 10 build (1511) using the Media Creation Tool. Previously it was possible to upgrade using the tool but Microsoft has withdrawn the update files.
Users who use the Media Creation Tool to do a clean install of build 1511 are presented with an older Windows 10 build as released in July (10240) instead. The reason appears to be that Microsoft wants users to update through Windows Update only.
Build 1511, also known as Threshold 2, Fall Update and November Update is rolled out to users this month. Users who install Windows 10 in November this year have to wait a month before they get access to this update. The reason is that Microsoft provides Windows 10 users a 31 day period to return to their previous operating system. After that period the November update is automatically downloaded and installed.
Previously Microsoft recommended users to use the Media Creation Tool for quick updates, it appears the company has now changed its mind.