Get the full Install macOS app from Terminal

Why it happens

Software Update only downloads what your Mac needs right now, which is often a small update. The full installer is the complete Install macOS app, which you need to make a bootable USB installer or to install macOS on another Mac. Terminal can fetch it straight from Apple.

How to fix it

1. Open Terminal. It's in Applications > Utilities, or press Command-Space, type Terminal and press Return.

   Terminal

2. Copy the command from the Terminal box further down this page and change 26.0 to the exact version you need.

3. Paste it into Terminal, press Return and wait. The download is several gigabytes, so stay on a good connection and keep the Mac awake.

4. When Terminal says it's finished, look in Applications for the Install macOS app.

Still not fixed?

1. If Terminal says it can't find that version, it may not be offered for your Mac. Check the number and try another version your Mac supports.

2. Not enough space? Free some room in General > Storage. The installer needs plenty of free space to download and unpack.

   General›Storage

3. If the download stops partway, check your connection and run the same command again.

4. If you only want to update this Mac, use General > Software Update instead. It's simpler and needs no Terminal.

   General›Software Update

5. If the download keeps failing on a good connection, or the installer won't open, contact Apple Support.