The release of the final version of macOS Sierra being recent, a large number of users have not yet installed it on their Mac. A situation that Apple does not seem to really appreciate and which pushed it to use the big means.
Indeed, the apple company is now forcing users to migrate to the new macOS Sierra operating system. There is no longer any question of inviting them to download the update: the download is done automatically in the background, without warning.
However, this is not the case for the installation of the new operating system. Here, Apple requests the user’s agreement and the operation is only launched if the user gives his authorization. So it can delete the file at any time and therefore free up some disk space. Also, the download is not done if the user does not have enough space on his computer and the installation file can even be deleted in the event that its presence slows down Mac performance due to a lack of storage.
Finally, be aware that this automatic download operation has already started, but its “official” launch is planned for next week. If you are using a macOs Sierra compatible Mac, you are warned! To avoid this inconvenience, go to System Preferences> App Store and deactivate the option Download the latest updates available in the background.