Jim Dalrymple at The Loop is reporting that starting today, the Mac App Store will automatically download the macOS Sierra installer:
It’s important to note that this is not an automatic installer—this process will only download the update in the background, and then alert you that it is available to install. You can choose to install it when its convenient. You can also choose to ignore the update.
Apple says that if your machine does not meet the requirements for Sierra, or is running low on disk space, the update won’t be downloaded. If it is downloaded and disk space gets tight, the system will delete the installer. The installer will not be downloaded unless the Mac App Store preferences are set to automatically download updates.
It’s easy to understand why Apple would make this change. The company, third-party developers and users all benefit from everyone being on the latest release. I imagine that many users may start to install a new OS then skip it when they see that the download will take 45 minutes.
That said, I do have a couple of concerns. People on limited data plans may not like the surprise of a multi-gigabyte download going on in the background.
More importantly, this move may lessen the perceived significance of installing a major update to macOS. While Sierra doesn’t bring sweeping changes, putting it on the same level of updating Tweetbot feels a little problematic.
That said, if a user doesn’t know to backup their data or check for third-party application conflicts before updating their OS, auto-downloading won’t get them into any more trouble.