The public beta of macOS 15 Sequoia is available. Unfortunately, it is only limited to the users who enroll their Mac in Apple Developer program. In this post, I will show you how to create a macOS 15 Sequoia bootable USB so you can test it out on your Mac.
First, download the macOS Sequoia Install Assistant pkg installer from this link.
Next, double click the .pkg file to copy the macOS 15 Beta App to the Application folder.
Connect a USB drive to Mac and find the usb name with the following command:
Run the followig command to create a bootable USB of macOS Sequoia:
sudo /Applications/Install\ macOS\ 15\ beta.app/Contents/Resources/createinstallmedia –volume /Volumes/USB_Volume_Name
This will first erase the USB drive to HFS+ and copy all files and folders to the target USB drive. Once it is done, it makes the USB bootable by writing boot sector to the physical USB.
To boot from Sequoia installer USB on Intel Mac, restart your Mac and hold the Option key. Wait 30 seconds and choose the volume name (Install macOS 15 Beta) to start installing Sequoira. For Apple Silicon Mac, power off the device and keep pressing the Power key. This will load startup options where you can see the bootable volume on the screen.
Before creating the bootable USB, make sure the file is correct and has not been tampered with. You can use a tool like MD5 or SHA-1 to verify the file's integrity. This is a crucial step, as it ensures that the file is authentic and won't cause any issues during the installation process.