It took a few steps, but it wasn’t too bad once I understood the process.
macOS Pro 2020, M1.
You can use ChatGPT it'll guide you step by step
1️⃣ Format the USB drive first: I used Disk Utility to erase it with Mac OS Extended (Journaled) and GUID Partition Map. That’s required before creating the installer.
2️⃣ Download the full macOS Sequoia installer: I made sure to get the complete 13 GB version using the Terminal command:
softwareupdate --fetch-full-installer --full-installer-version 15.6.1
3️⃣ Create a bootable installer: Once Sequoia was in the Applications folder, I ran:
sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/SequoiaUSB
4️⃣ Boot from the USB: I shut down the Mac, held the power button to load startup options, and chose Install macOS Sequoia (the USB).
5️⃣ Erase the internal drive: In Disk Utility I formatted Macintosh HD as APFS + GUID, to remove macOS Tahoe completely.
6️⃣ Reinstall Sequoia: Then I ran the installer normally.
Since all my work and files were already synced with iCloud, I didn’t lose anything — everything came back automatically after signing in.
Note: After the installation finished, I had to reinstall Microsoft Teams and Outlook, then sign back into my accounts. Everything synced normally once I logged in.