If you receive the error reading "This disk has S.M.A.R.T errors. This disk has a hardware problem that can't be repaired. Back up as much of the data as possible and replace the disk" when installing macOS Monterey, your hard drive is likely falling or isn't an original Apple drive.
To verify whether your internal hard drive has S.M.A.R.T errors, open Disk Utility, right-click your internal hard drive and select "Get Info." Then you can scroll down to check the S.M.A.R.T status. If it reads Verified, your hard drive is in good shape. If it says "Failing," your drive is likely having issues.
As the error suggested, it's recommended to back up your Mac before trying any fixes. You can make a Time Machine backup or clone your Mac with a tool like iBoysoft DiskGeeker, which is a comprehensive disk management software for Mac that provides all necessary tools in one package.
To fix "This disk has S.M.A.R.T errors" error on Mac, you can repair your hard drive with First Aid from macOS recovery. If it continues to report the S.M.A.R.T error, consider erasing your Mac to complete a fresh install. If the issue persists, you may need to replace your hard drive.
If you have a non-Apple hard drive, what you need may only be a firmware update. The Monterey upgrade includes a firmware update that requires an Apple hard drive to be installed. Therefore, you should try installing the original Apple hard drive on your Mac and installing the Monterey update on it to get the firmware update. Then insert your current hard drive and retry the upgrade.
If you still receive the S.M.A.R.T error, try the following steps:
- Find a Mac that's running macOS Monterey or reinstall the original hard drive and install Monterey on your current Mac.
- Connect the non-Apple hard drive externally to the Mac.
- Download iBoysoft DiskGeeker.
- Clone the macOS Monterey startup disk to the externally-connected hard drive.
- Reinstall the non-Apple hard drive to use Monterey.