how to install Mac OS on a new HD

Hi Seven0117,

To install macOS on a new hard drive, you'll need to format (erase) it for macOS using Disk Utility.

If you're attempting to migrate your data onto the new hard drive, follow these steps:

1. Open Disk Utility, located in Applications -> Utilities. If you can't start up to macOS, boot to macOS Recovery (hold down Command-R at startup), then select Disk Utility.
2. Connect the hard drive to your Mac.
3. In Disk Utility, select View -> Show All Devices.
4. Select the top level of the hard drive and click Erase. Choose these options, then click Erase:
   1. Name: Whatever you want
   2. Mac OS Extended (Journaled) if you're running macOS High Sierra or earlier; APFS if you're running macOS Mojave or later
   3. Scheme: GUID Partition Table/Map
5. When the erase is finished, quit Disk Utility.
6. To reinstall macOS: Download macOS Big Sur from the App Store, or choose one of these older versions. If you're in macOS Recovery, choose Install macOS instead.
7. You can migrate your data from your previous drive in Setup Assistant or Migration Assistant.