If an error occurred while updating or installing macOS

The message might say that an error occurred while downloading, preparing, or installing, or that the software is damaged, could not be verified, or failed to personalize. The cause of such messages can vary, and sometimes they're only temporary. Try these solutions.

Check storage space

If the message says that your Mac doesn't have enough storage space, free up storage space.

Check your internet connection

The installer needs a stable internet connection to download macOS and get firmware and other information specific to your Mac model. Make sure that your Mac is connected to the internet.

Install from macOS Recovery

To ensure that no other software on your Mac can interfere with installation, install macOS from macOS Recovery.

For the same reason, if you’re installing via the App Store or Software Update instead of Recovery, it might help to start up in safe mode before installing.

Repair your startup disk

Use Disk Utility to repair your startup disk.

If you’re using a previously downloaded installer that your Mac says is damaged or can’t be verified, delete it and download the installer from Apple after repairing your disk.

Revive or restore Mac firmware

Rarely, if using a Mac with Apple silicon or Mac with the Apple T2 Security Chip, you might need to revive or restore Mac firmware to resolve a persistent macOS installation issue.

Erase your Mac

If none of the previous solutions work, erase your Mac and reset it to factory settings.

If you need help

If the installation issue persists or you need help, contact Apple Support.