How to Download and Install macOS High Sierra Offline

MacOS High Sierra, a powerful and user-friendly operating system, can be installed offline using the methods outlined below. This guide covers everything from downloading the installer to creating a bootable USB drive for installation.

Download macOS High Sierra for Offline Installation

To successfully install macOS High Sierra off your network, you first need to download the installer. Follow these steps to complete the process:

Open the Mac App Store

Launch the Mac App Store on your Mac by clicking on the App Store icon in the Dock. If you can't see it, you can open it via Spotlight or from the Finder.

Search for macOS High Sierra

Once the Mac App Store is open, use the search bar to find macOS High Sierra.

Click the Download Button

Click the Download button. The installer will be saved in your Applications folder. This is the initial step in downloading the necessary files for offline installation.

Create a Bootable USB Drive (Optional but Recommended)

Once you have the installer file, you'll need to create a bootable USB drive to use for installation. Follow these steps to create a bootable installer:

Prepare the USB Drive Ensure that you have a USB drive with at least 8 GB of storage. Format the USB Drive Open Disk Utility located in the Utilities folder inside Applications. Select your USB drive from the list on the left. Click on Erase. Choose Mac OS Extended (Journaled) as the format and name it appropriately, e.g., "High Sierra Installer" or "macOS Installer". Format the USB drive. Create the Bootable Installer Open Terminal from the Utilities folder. Run the following command to create the bootable installer: sudo /Applications/Install macOS High --volume /Volumes/[USB Drive Name] --nointeraction

When prompted, press Enter and enter your admin password. This will create the bootable installer on your USB drive.

Using the Bootable USB Drive for Installation

With the bootable USB drive ready, you can proceed to install macOS High Sierra:

Restart Your Mac

Shut down your Mac and restart it by holding down the power button.

Select the USB Drive

During startup, hold down the Option key. This will bring up the boot menu, where you can select the USB drive to start the installation process.

By following these steps, you can successfully download and prepare macOS High Sierra for offline installation. For unsupported Macs, you can find further guidance in the section below.

Installing macOS High Sierra on Unsupported Macs

For unsupported Macs, the process can be a bit more complicated. Here’s how you can get started:

Visit Apple's Certified Website

Go to the official page to find the listing of supported Mac models and download instructions. Ensure you have a supported Mac before proceeding.

Watch a Tutorial Video

For unsupported Macs, you might need a patcher or a workaround. Dosdude, a YouTuber, has created a patcher that allows you to download unsupported macOS releases. Watching the full video and following the instructions carefully is recommended to avoid damaging your Mac.

Replace VIDEO_ID with the actual video ID from the Dosdude's tutorial video.