This error occurs because Apple’s older security certificates embedded inside the installer package have expired.
You will need a USB flash drive with at least of space. Format the USB Drive : Open Disk Utility (Applications > Utilities). Select your USB drive in the sidebar. Click Erase and use these settings: Name : MyVolume (or any simple name without spaces). Format : Mac OS Extended (Journaled) . Scheme : GUID Partition Map . Create the Media via Terminal : Open Terminal .
Follow the on-screen prompts, accept the software license agreement, select your freshly formatted primary drive as the destination, and allow the installer to run.
For those committed to High Sierra, having a verified DMG file on hand and knowing how to create a bootable USB installer is essential. Whether you're performing a clean installation, upgrading an aging Mac, or building a Hackintosh, this guide provides the comprehensive instructions you need to succeed. macos high sierra 10136 dmg install
Open Terminal and run the following command (assuming your USB is named "MyVolume" and the installer is in Applications): sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume Type your password and wait for the process to finish. Phase 3: Installing macOS High Sierra 10.13.6 With your bootable USB ready, you can now install the OS.
If the App Store blocks your download because your current Mac is "too new," you can use Apple's official developer distribution links to fetch the package directly.
Before proceeding, ensure your Mac supports macOS High Sierra. The general hardware requirements include: (Late 2009 or newer) MacBook Air (Late 2010 or newer) MacBook Pro (Mid 2010 or newer) Mac mini (Mid 2010 or newer) iMac (Late 2009 or newer) Mac Pro (Mid 2010 or newer) Select your USB drive in the sidebar
High Sierra is a significant upgrade over its predecessor, macOS Sierra, because it focused on under-the-hood technologies rather than just new features. As Apple described it, the update "brings powerful new storage, video, and graphics technologies to the Mac". The final 10.13.6 update, released in July 2018, added multiroom audio support for iTunes and included numerous stability and security improvements.
A flash drive with at least 16 GB of capacity (all data on this drive will be erased). 3. Create a Complete Backup
command, the static DMG is transformed into a living, breathing bootable tool. It is a process of turning data into a key that can unlock a dormant machine. 3. The High Sierra Refinements Why go through the trouble? High Sierra brought the Apple File System (APFS) Scheme : GUID Partition Map
sudo codesign --remove-signature /Applications/Install\ macOS\ High\ Sierra\ 10.13.6_17G66.app/Contents/Resources/createinstallmedia
On the main menu, select (or Reinstall macOS ) and click Continue .
The process will take 10–20 minutes. You'll see progress indicators as the drive is erased and the installer files are copied. When you see "Done," the bootable USB is ready for use.