If you’re trying to create a macOS USB installer using Terminal and run into the error message … IA app name cookie write failed … the issue may be due to Terminal not having Full Disk Access.

Apple released macOS Monterey last October and if you’re finally ready to upgrade, the easiest option is to upgrade your existing installation of macOS to macOS Monterey provided your existing Mac is a supported device. If your Mac supports macOS Monterey, simply download macOS Monterey from the App Store and run the installation. Follow the on-screen prompts and in about 45 to 60 minutes, your Mac should be up and running on macOS Monterey.

To create a macOS Big Sur bootable USB installer, you will need a USB Flash Drive. Apple suggests at least 14GB of available storage so get a USB Flash Drive with at least 16GB of storage. Keep in mind all data on the USB Flash Drive will be erased so don’t use one with data that you want to keep. Name the USB Flash Drive “MyVolume”.