Recently my sister asked me to reinstall the macOS High Sierra on her iMac because it stopped working correctly. I thought that it would be easy to do but I was mistaken. I successfully installed the macOS Mountain Lion (when using the NetBoot it automatically selects the version of macOS with which the iMac was shipped with). But then I was facing multiple issues trying to update macOS from Mountain Lion to High Sierra via the Mac App Store.
After downloading a copy of macOS High Sierra from the Mac App Store, I started installing the update. The Mac rebooted, and it seemed that everything was going well, but it was not. The progress bar did not move at all, or moved very slowly. I waited a few hours…
I began to figure out what was going on and found out the following. Attempting to download macOS High Sierra from the Mac App Store I found that a small 19 MB version of the “Install macOS High Sierra.app” downloads to the “Applications” folder, rather than the complete 5.2 GB installer application. That’s the problem.
The tiny 19 MB incomplete installer requires an internet connection during usage to download the rest of the High Sierra update files. Additionally, it does not allow me to create a macOS High Sierra USB installer drive for use on multiple computers.
I’ve found a new workaround, and in this tutorial, I’ll show you how to download the complete macOS High Sierra “Install macOS High Sierra.app” file from Apple server using the “macOS High Sierra Patcher” app instead of via the Mac App Store.
About the app
In this workaround, we’re going to use the “macOS High Sierra Patcher” app that is intended for those with unsupported Macs and Hackintosh users, but any Mac user can use the app to be able to download the complete installer file from Apple servers.
Note! This method relies on a third party app from an unverified third party source. If you are not comfortable with using unvetted and unverified software, do not follow this process.
Go to the official website of the “macOS High Sierra Patcher” app here and download the app.
Launch the “macOS High Sierra Patcher” app.
Note! By default, macOS preventing apps from unidentified developers or sources from being launched. So you most likely will get an alert message that says: “macOS High Sierra Patcher.app can’t be opened because it is from an unidentified developer”. To allow just one specific app to run do the following:
- Hold down the
Controlkey and click the app icon. From the contextual menu choose
- A popup will appear asking you to confirm this action. Click the
Ignore everything about patching, instead pull down the “Tools” menu and choose “Download macOS High Sierra…”. Confirm that you want to download the “Install macOS High Sierra.app” app, and then point it to a location to save on the hard drive.
Close the “macOS High Sierra Patcher” app when the download is complete and locate the “Install macOS High Sierra.app” file you downloaded.
Done! Now you have the complete “Install macOS High Sierra.app” file downloaded.
You can confirm that you have the complete “Install macOS High Sierra.app” app by getting info on the file. The complete installer should be around 5.2 GB rather than the tiny 19 MB incomplete installer that requires additional downloads.
Let me know in the comments section if you know another way to download the complete macOS High Sierra installer app rather than the tiny incomplete installer.
If this article helped you then please leave a comment.
Thanks for reading!