This common error happens because the security certificate built into older installers has expired. To fix it: Disconnect your Mac from the internet.
For users resurrecting a 2010 Mac Pro with a Metal-capable GPU, or a 2012 MacBook Pro that slows to a crawl under Catalina or Big Sur, High Sierra 10.13.6 is the sweet spot: modern enough for web browsing and security, but light enough for old hardware.
To get a , your safest option is to acquire the file directly through official Apple channels or clean native scripts. While older operating systems are tucked away from the main storefronts, Apple still provides backdoors via the Mac App Store and direct package formats for legacy hardware restoration.
[Download macOS High Sierra via Mac App Store](apple.com sierra/id1246284741) Step 2: Download the Installer Click the button on the App Store page.
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume (Replace 'MyVolume' with your USB drive's actual name) Cross-Platform Tools : On a Windows PC, you can use software like UUByte DMG Editor to "burn" a High Sierra DMG to a USB drive. Microsoft Community Hub Key Features of Version 10.13.6 macOS High Sierra - App Store download macos high sierra 10.13.6 dmg mac
macOS High Sierra 10.13.6 is more than just an old operating system. It is the final version of High Sierra, representing the last update before Apple transitioned to macOS Mojave. For many users, it serves as a critical bridge: it supports APFS (Apple File System), optimizes Metal 2 graphics, and—most importantly—still runs 32-bit applications, which later versions of macOS dropped entirely.
Set the Name to Untitled , the Format to , and the Scheme to GUID Partition Map . Click Erase . Close Disk Utility and open Terminal .
A pure .dmg (Disk Image) file format is specifically ideal for:
The system will download Install macOS High Sierra.app into your folder. Method 2: Direct Terminal Download Command This common error happens because the security certificate
Once you have the installer in your Applications folder or a DMG file ready, you can proceed with the installation. Method A: Upgrade Installation
Apple provides direct DMG downloads for legacy systems that cannot access the App Store. Apple Support Direct Download: Apple Support Download page and look for the High Sierra link. Install the Installer: Double-click the downloaded file to open it. Inside, run the file to install the installer app into your Applications folder. Apple Support 4. Third-Party Alternative: Mist
As of 2026, many older Mac users (circa 2009–2017) still rely on High Sierra for its unique balance of performance and compatibility.
Click the official link below using the Safari browser on a compatible Mac: To get a , your safest option is
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Before running the installation, ensure your hardware is fully compatible with macOS 10.13.6: Late 2009 or newer MacBook Air / Pro: Late 2010 or newer Mac mini / iMac: Late 2009 or newer Mac Pro: Mid 2010 or newer Memory: Minimum 2GB RAM (4GB or more highly recommended) Storage: At least 14.3GB of available storage space ⚠️ A Note on Third-Party Download Portals
Downloading and Installing macOS High Sierra 10.13.6 Whether you need to revive an older Mac or create a bootable installer for troubleshooting, obtaining macOS High Sierra 10.13.6 requires specific steps because Apple has transitioned most legacy downloads to the Mac App Store. 1. Check System Compatibility