Clean up your temporary directory by running rm /tmp/HighSierra.dmg .
Beyond this headline feature, the 10.13.6 update included critical bug fixes and security patches:
Before downloading the ISO, ensure that your target hardware (or the profile configured in your virtual machine) matches Apple’s official system requirements for High Sierra. 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 How to Create a macOS High Sierra 10.13.6 ISO Legally macos high sierra 10136iso
If you need an ISO for a virtual machine or a bootable USB, you can create one from the official installer app using Terminal commands on a Mac: Download the Install macOS High Sierra.app from the App Store. command to create a blank disk image. createinstallmedia
hdiutil convert /path/to/your/installer.dmg -format UDTO -o ~/Desktop/HighSierra.cdr Clean up your temporary directory by running rm
This is a common issue caused by expired security certificates. To bypass it, disconnect your machine from the internet, open the Terminal during the installation setup, and roll back the system clock by typing date 0101010118 (which sets the date to January 1, 2018).
The system will open the Software Update panel and download Install macOS High Sierra.app into your folder. Method B: Using Terminal (macOS Catalina or Newer) command to create a blank disk image
The most straightforward .dmg or .app installer is fine for installation on a supported Mac via the App Store. However, for older Macs that are no longer supported by newer macOS versions or for "Hackintosh" systems (non-Apple hardware running macOS), an ISO file can be a more versatile tool for creating a bootable USB installer. A macOS High Sierra ISO image is usually larger, around 7–8 GB, because it contains a complete, bootable disk image [17†L30-L34].