But you can’t format the startup disk while your macOS is running. If you want to reinstall macOS or upgrade your macOS, you need to format your Macintosh HD startup disk.

Format the Startup Disk in macOS Recovery Mode Read More: How to Set Up Time Machine on Mac 2. If you haven’t set up your Time Machine backup drive, you can set up the drive now. And, for Macintosh HD, the startup disk, you can use Time Machine to back up your macOS as well as its stored data. For an external or non-boot volume, copy all your valuable files and folders, and paste them to another external storage device. Back Up Your Mac Hard Drive before Formattingīefore erasing your Mac hard drive be it internal or external, you must back up the drive to ensure zero data loss. Methods to Format Mac Storage Drive Without Data Loss 1. The next section discusses the correct way to format your Mac storage drive without data loss. DO NOT click the Initialize button unless it’s a new drive or you have recovered data from it. So, you end up losing your data.Īlso, when you connect a corrupt or unreadable external storage drive to your Mac, macOS will prompt you to initialize the disk. When your Mac storage drive has stored data on it, and you accidentally erase the drive in a new file system format, macOS removes all references to the data. Perfecting the storage drive in case Disk Utility fails to repair itīut storage drive formatting involves certain risks.Changing the file system format for cross-compatibility.

Resolving corruption or unreadable error of the storage drive.Preparing the startup disk to reinstall macOS.You may even need to manually format your internal or external Mac storage drive or volume in the compatible file system. MS-DOS (FAT) or exFAT format to make your external storage drive cross-compatible with both macOS and WindowsĪ new Mac with its built-in solid-state drive or hard drive comes pre-formatted with a file system that contains the macOS.Mac OS Extended format for macOS Sierra 10.12 or earlier.APFS format for macOS Ventura 13, Monterey 12, Big Sur 11, Catalina 10.15, or Mojave 10.14.

Different file system formats exist for different operating systems. Methods to Format Mac Storage Drive Without Data LossĪn internal or external Mac storage drive requires a compatible file system format to be accessible in macOS.

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