Regardless of the operating system you choose, external hard drives can be useful in many situations. Whether you need to move a few files to another system or want to do a quick backup, it never hurts to have a few available.
But an external hard drive is only useful if you can use it. If you are faced with permissions-related issues or unable to add files because the hard drive is locked, all use of a hard drive will be prevented. This is not often a major problem, and most of the time it is easy to solve.
What does it mean when a hard drive is locked on your Mac?
You may not be familiar with the concept of how to unlock an external hard drive on Mac. In part, this is because it can be related to a few different issues:
The drive is set to read-only permissions so you cannot add or delete files.
The external hard drive uses a partially supported file system such as NTFS, which macOS only supports as read-only.
The drive is encrypted, which means you cannot access it until you decrypt the hard drive.
How to unlock a hard drive on macOS
Now you know the likely reasons behind the locked drive. Let's examine the steps you can take to resolve these issues.
1. Resolving permission-related problems
Ctrl-click the drive icon in Finder, and then select get information. By doing Sharing and permissions Section, click on that Lock in the lower right corner and enter your username and password. Then check Ignore ownership of this volume. This way, your Mac will treat all files on the hard drive as if they belong to the current user, regardless of who they actually belong to.
If it is a recently formatted drive, you can change each of the permissions in the box above. That way you can change the permissions on Read Write for yourself, while the drive remains write-protected for other users. Here is a macOS disk permissions guide to help you understand the technical concepts.
2. Decrypt the external hard drive
To unlock an encrypted hard drive, Ctrl-click the drive icon in the main Finder view or in the sidebar. From the menu that appears, select the option Decrypt "drive name" and enter the password. This only works if you know the password. And if you don't, you can still format the drive, which we will get into a little below.
3. Resolve the write-protected external hard drive problem
Does your external hard drive show as read-only on your Mac? This happens because the drive is formatted using Microsoft's NTFS file format. In macOS, you can only read data carriers in this format, not write to them. As a result, you will not be able to add, change, or delete any files.
If you purchased a Seagate external hard drive, it comes with the Paragon driver so that you can read and write data on Windows and Mac interchangeably without formatting the drive. The Seagate website lists two separate versions, one for macOS 10.10-10.15 and another for the Macs running the M1 chip.
For other drives, they most likely use exFAT, which has no realistic file or partition size limits, or they require complicated ACLs and a file association system like NTFS. In the event of a crash, you could lose data.
Note: Mac computers with Apple Silicon must change the startup disk security settings to Reduced Security for the software to work properly. To do this, start your Mac in macOS recovery. Choose Utilities> Startup Security Utility and change the security policy.
How to format external hard drive for Mac
Now that you know how to unlock your external drive, it's time to format it for use on your Mac. Before proceeding, note that This will erase all of the data on the drive. Unless you are sure you don't need any data, you should back it up first.
You should also consider how you are going to use the drive. Different file systems are better suited for certain tasks, so you need to select the correct file system for your needs. If you're not sure, take a look at our review of the best Mac file systems for external drives.
Open that Disk utility App. In the left area you can see the list of internal and external drives separately. Choose now View> Show all devices to view the top-level storage devices, containers, and finally all volumes in each container.
Select the external storage device (not the container or the volumes it contains). Click in the toolbar Extinguish. Enter the hard drive name, then choose your preferred option for both format and Partition scheme. By default, the option is set to APFS and GUID partition mapping scheme. When reformatting is done, click complete. At last click on the Eject next to the volume in the sidebar.
Name the option Extinguish makes it obvious that the process is erasing your data, but this creates confusion in other ways. When looking at how to format an external hard drive for Mac, you might not be looking for an option called "Erase".
How to lock a hard drive on Mac
If you're wondering how to lock an external hard drive on Mac, it is somewhat similar to unlocking it. To render a drive read-only, Ctrl-click the drive, then choose get information. Deactivate here Ignore ownership of this volume at the bottom of the window.
By doing Share & permissions Section, change Read Write to Read only for each category you want to change. This prevents unwanted users or groups from deleting, adding, or modifying files on the drive.
It is very easy to encrypt an external hard drive on Mac. Ctrl-click the drive, then choose Encrypt "DriveName" on the hard drive. Choose a password, enter it again and leave a password hint. Then click Encrypt hard drive and wait for the process to finish.
External drives are not displayed?
Most of us use external hard drives from time to time. If you only use Mac computers at home, you probably won't have any problems. You just need to pay attention to the compatibility of Time Machine backups.
However, if you have a Mac at home and a Windows PC in the office, either exFAT or Seagate drives are your best options. However, sometimes the external hard drive may not show up completely. Fortunately, there is a long list of troubleshooting steps that you can follow to resolve these issues.
External hard drive not showing up on Mac? How to fix it
External hard drive not showing up on your Mac? Below is a troubleshooting guide that will help you get your external hard drive or flash drive working again.
About the author
(167 published articles)
With an M.Optom degree in ophthalmology, Rahul taught for many years at the college. Writing and teaching others is always his passion. He's now writing about technology and making it digestible for readers who don't understand it well.
From Rahul Saigal
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