Select , click Continue , and follow the on-screen prompts to select your internal drive and finish the installation. For an Upgrade Installation (Keeping Existing Data)
Insert your USB flash drive. Right-click the drive in TransMac and select .
hdiutil create -o /tmp/HighSierra -size 8000m -layout SPUD -fs HFS+J Use code with caution. Mount the newly created blank disk image: macos high sierra download dmg install
: High Sierra introduces the APFS file system natively for SSDs. If the installation fails at the drive conversion stage, verify that your target drive's partition scheme is explicitly set to GUID Partition Map rather than MBR.
Select your USB drive from the left sidebar, click , and set the parameters to: Select , click Continue , and follow the
Simply having the DMG is not enough to install the OS. You cannot boot from a DMG file directly.
Click . The Mac will copy files and restart several times. Do not unplug the USB drive or turn off the computer during this phase. 5. Troubleshooting Common Installation Errors hdiutil create -o /tmp/HighSierra -size 8000m -layout SPUD
Because High Sierra is legacy, some App Store or iCloud features may behave incorrectly. For daily use on supported hardware, consider Mojave (10.14) or Catalina (10.15) if possible. Use High Sierra only when hardware limitations force you.
Select your internal hard drive (usually named Macintosh HD) and click .
Installing macOS High Sierra via DMG is feasible but requires careful sourcing of the installer file and manual handling of certificates. The bootable USB method offers the most control, while direct installation is simpler for in-place upgrades. Users should prioritize security mitigations due to the OS’s end-of-life status.