Macintosh HD vs. Macintosh HD- Data in Mac: Why Grayed Out

🗓️ July 17, 2023 By ✍️ Jaysukh patel

If you have a MacBook running on the latest macOS, you will find two disks labeled: Macintosh HD and Macintosh HD-Data. Starting from the macOS 10.15 Monterey update, Mac’s internal hard disk is divided into two parts. One is called Macintosh HD, which contains the macOS and is the read-only volume of the system files. While the other is labeled Macintosh HD- Data which has all the other files you store in your MacBook. 

This post focuses on the difference between the Macintosh HD and Macintosh HD- Data drives available to the users after the macOS 10.15 Monterey upgrade. Let us look at these drives individually and then talk about the differences.

What is Macintosh HD Drive?

The Macintosh HD drive is a system volume that contains all the system files and the operating system of your MacBook. You might find this drive greyed out when trying to delete files from it.

This drive is greyed out because Apple does not allow users to delete, erase, or edit the data in this drive as it contains information about the operating system.

If these files are erased or edited, the MacBook will fail to start up, and you will have to reinstall the entire macOS again. The Macintosh HD drive file format is set as APFS or APFS (Encrypted) and can not be reformatted or changed to other system file formats.

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What is Macintosh HD- Data Drive?

Unlike the Macintosh HD drive, the Macintosh HD- Data drive contains all the user data like photos, videos, documents, and all the other files saved or stored by you on the Mac.

You can erase, delete or edit files stored in this drive as the users get read-write access to this drive. The deletion of the files stored in this volume won’t affect the booting-up process of the MacBook as it does not contain any system files of the operating system.

Similar to the Macintosh HD drive, the system format for this drive is also APFS or APFS (Encrypted), which cannot be changed to other file systems.

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What is the Difference Between Macintosh HD and Macintosh HD- Data?

The main difference between the Macintosh HD and Macintosh HD- Data drives is the contents and files stored in the respective drives.

Macintosh HD is a system volume and contains all the scripts, system apps and files, and the macOS. In contrast, Macintosh HD- Data has all the user data and personal files like audio, documents, videos, etc. 

Another significant difference between the Macintosh HD and Macintosh HD- Data is the mode of access to the drive’s contents. Macintosh HD is a read-only system volume meaning no data or files can be erased or edited in this volume, and it controls the information for starting up your Mac.

In contrast, the Macintosh HD- Data volume is a drive with read-write access to the contents meaning all the files in it can be erased or edited without affecting the functioning of the MacBook.

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Besides the differences, both the volumes and one thing in common- Macintosh HD and Macintosh HD- Data show up in the finder app as a single Macintosh HD drive.

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Macintosh HD or Macintosh HD- Data. Which Drive to Erase?

Knowing which volume you should erase or wipe out for your desired purpose is crucial. This section sheds light on the various reasons a Mac user should erase the specified volumes.

  • For reinstalling the macOS

As we have discussed before, the Macintosh HD volume contains all the system apps, data, and macOS. This data is why this drive is partitioned as a separate volume to prevent overwriting of vital operating system data by accident.

The first step for reinstalling macOS is wiping out the startup disk of your MacBook by heading to the macOS recovery mode. This means deleting or cleaning up all the system data stored in the Macintosh HD volume.

By wiping out the Macintosh HD system volume, the users can free up the space required to install the new operating system while building a safe and stable condition for reinstalling the macOS.

You might run into installation failures and errors if you start installing the latest macOS without erasing the Macintosh HD volume.

  • For Downgrading the macOS

If you face some problems or glitches with the current macOS installed on your device, you might want to downgrade the macOS to an earlier version to fix this issue. The process of downgrading the macOS involves erasing both Macintosh HD and Macintosh HD- Data volumes.

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As for a reason for erasing the Macintosh HD- Data drive, when downgrading to an earlier version of the macOS, the system will create a new Macintosh HD- Data folder for storing all the user data.

If you don’t delete that drive, two drives with the same name- Macintosh HD- Data will be created. The presence of two drives with the same name can cause a lot of problems for your Mac. Hence, it is encouraged to create a backup of all the data stored in Macintosh HD- Data volume before cleaning it off for downgrading the macOS.

The differences between the Macintosh HD and Macintosh HD- Data volumes in your MacBook were successfully discussed in this article. Keep in mind the key points explained in this post to avoid any problems while reinstalling or downgrading the macOS on your Macs.

We conclude all the necessary details about Macintosh HD and Macintosh HD- Data volumes and hope you can grasp all the information delivered to you.

Q & A→ 

  1. Macintosh HD and Macintosh HD- Data which to erase?

→ If you are reinstalling the macOS on your MacBook, then erasing the Macintosh HD volume is the best way to do it for avoiding errors. In case of downgrading to an older version of the macOS, erasing both the Macintosh HD and Macintosh HD- Data volumes are crucial.

  1. Macintosh HD and Macintosh HD data where to install macOS?

→ Since all the system files and the macOS are stored in Macintosh HD system volume, the new macOS should also be installed in the same volume.

Jaysukh patel
Jaysukh patel

Jaysukh Patel is the founder of howoiSolve. Also self Professional Developer, Techno lover mainly for iPhone, iPad, iPod Touch and iOS, Jaysukh is one of responsible person in his family. Contact On: [Or]

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