How to download and install macOS Sequoia

Installing macOS Sequoia with an offline installer involves a few steps. Please note that the specifics may vary slightly depending on the version of macOS you’re installing.

Prerequisites:

Backup Your Data: Ensure you have a complete backup of your important data.
Offline Installer: You’ll need a macOS installer app or a bootable USB drive with the macOS installer.

Steps to Install macOS from an Offline Installer:

Create a Bootable USB Drive (if needed):
- Download the Installer: If you already have the macOS installer file (usually a .app file) downloaded from the Mac App Store or Apple’s website, you can create a bootable USB drive.
- Prepare the USB Drive: Plug in a USB drive with at least 16 GB of space. Open Disk Utility and format the drive as Mac OS Extended (Journaled) with a GUID Partition Map.
- Create the Bootable Installer:
  - Open Terminal.
  - Enter the command to create the bootable installer:
```
sudo /Applications/Install\ macOS\ sequoia.app/Contents/Resources/createinstallmedia —volume /Volumes/MyVolume
```
    Replace /Volumes/MyVolume with the name of your USB drive.
  - Follow the prompts to complete the process.
Boot from the Installer:
- Insert the bootable USB drive.
- Restart your Mac and hold down the Option (⌥) key immediately after the startup chime.
- In Startup Manager, use the arrow keys to select the USB drive and press Enter.
Install macOS:
- Once booted from the USB drive, select your language and click Continue.
- If necessary, open Disk Utility and format the target disk as APFS (or Mac OS Extended (Journaled) for older macOS versions).
- Follow the prompts to select the installation disk and click Install.
- After installation, your Mac will restart. Follow the on-screen setup instructions.

Tips:

While the installation itself is offline, you might need an internet connection for activation or updates.
Ensure the macOS version is compatible with your Mac model.

If you want, I can also compress this further into a short 8–10 step quick checklist so it’s easier to follow during installation.