If you’re on a Mac with recent macOS release (Sierra or El Capitan), then Apple is defaulting to try and automatically downloading the 5GB installer for macOS High Sierra in the background to your computer. When the download completes, the Mac then sends you a notification suggesting that High Sierra is ready to install, with the notification only having two options; “Install” and “Details”. Some users may find this convenient to automatically download a major software update and casually suggest to install it onto a Mac, but other users may be less than excited about this behavior, particularly if you’re not yet ready to install macOS High Sierra onto a computer.
If you do not want macOS High Sierra to be automatically downloaded onto a Mac, maybe because you’re avoiding the macOS update or postponing it while a particular bug or issue is sorted out, we’ll walk through a few steps on how to prevent a Mac from automatically downloading the MacOS High Sierra installer.
How to Stop MacOS High Sierra Installer from Downloading Automatically
The first thing you can to prevent High Sierra from automatically downloading do is toggle system preferences to prevent the automatic downloading of updates in the background.
- Go to the Apple menu and choose “System Preferences”
- Go to the “App Store” panel
- Uncheck the box next to “Download newly available updates in the background”
- Exit System Preferences
This alone should prevent macOS Sierra or Mac OS X El Capitan from downloading the “Install macOS High Sierra” file onto your Mac into the Applications folder, and prevent from sending the notification that it’s ready to install.
Some Mac users may want to maintain automatic software downloads and updates however, but still avoid macOS High Sierra and the macOS High Sierra installer. Or perhaps you want to be absolutely certain that the Mac App Store does not download the installer for High Sierra. The next tip will detail a trick to accomplish that.
How to Completely Prevent the Mac App Store from Downloading the MacOS High Sierra Installer
If you’re committed to avoiding macOS High Sierra for whatever reason, you can completely prevent the “Install macOS High Sierra” application from ever downloading via the Mac App Store with this trick, which basically spoofs a copy of the installer and locks it down so that it can’t be overwritten. If you want to install High Sierra down the road, you will need to undo this and remove the spoof installer.
- From the Finder of Mac OS, go to the Applications folder
- Look for the legitimate “Install macOS High Sierra” in the directory, and if it exists, delete it by dragging to the Trash
- Locate a small application in the /Applications folder, like “Launchpad”
- Duplicate the selected Launchpad app by selecting Launchpad then hitting Command+D (or going to the File menu and choosing “Duplicate”)
- Rename the “Launchpad copy” file to “Install macOS High Sierra” – the name must exactly match the original authentic macOS High Sierra installer
- Now choose to “Get Info” on the freshly named fake “Install macOS High Sierra” app by selecting it and hitting Command+i (or going to the File menu and choosing ‘Get Info’)
- Click the “Locked” checkbox button to lock down the renamed app, then close the Get Info window
You can confirm this has worked by opening the Mac App Store and trying to download the MacOS High Sierra installer, which will fail with a message stating “macOS High Sierra failed to download”.
Essentially what you have done is taken another system level app from Apple (in this case Launchpad, but you can use another system app if you want), made a copy of it, renamed it to “Install macOS High Sierra” and locked it so that the file can not be changed or overwritten. This means when the App Store attempts to download MacOS High Sierra it will fail because the system will think the High Sierra installer file already exists, and discover that it is locked and can not be overwritten.
Important: This completely prevents the App Store from being able to download the MacOS High Sierra installer as long as the file exists in the Application folder. You will not be able to install macOS High Sierra on the Mac for as long as that renamed Launchpad / fake Installer exists in the Applications directory. If you want to reverse this, simply delete the fake “Install macOS High Sierra” app, or Get Info again and unlock the file, and then move the item
Why does macOS High Sierra Installer automatically download in the first place?
Apple has decided to automatically download the macOS High Sierra installer onto Macs running El Capitan or Sierra, a support document states the following:
If you’re using OS X El Capitan v10.11.5 or later, High Sierra conveniently downloads in the background, making it even easier to upgrade your Mac. When the download has completed, you receive a notification indicating that High Sierra is ready to be installed. Click Install in the notification to get started.
If you want to install High Sierra later, just dismiss the notification. Install it at any time by opening the file named Install macOS High Sierra from your Applications folder, Launchpad, or Spotlight. Or delete the installer by dragging it to the Trash. You can always get it again from the App Store.
This aggressive automatic download push for High Sierra was pointed out 512pixels and Tidbits, both of which make various good points about why it may not be a great idea to automatically download a 5.2GB file in the background, let alone try and install a brand new operating system, which is not without some reported problems, onto unsuspecting users, and without even backing up their computers beforehand (which would prevent a potential easy downgrade from macOS High Sierra to what you had before).
Of course another option that is less aggressive is to disable Notifications and alerts in Mac OS completely by enabling a 24/7 Do Not Disturb mode, which will simply prevent the “install macOS High Sierra” alerts from showing up on screen, but it wouldn’t prevent the download. Personally, I hate notifications and alerts of all kinds on my Mac and use the 24/7 Do Not Disturb trick so that I’m not pestered by nagging alerts and inconsequential distractions, but many users really like the alerts feature and may not find that as a reasonable alternative.
Of course if you’re already on High Sierra, none of this is applicable to you, and if you don’t mind that High Sierra is possibly downloading in the background and pushing to install, you won’t care much about this either. And to be perfectly clear, this is not unique to High Sierra, Apple was also automatically downloading Sierra to Macs that were running El Capitan as well. Nonetheless, if you don’t like auto-downloading large files or system software, you may appreciate stopping the behavior on your own Mac or others you manage.