External Disk For Mac

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An incompatible file system, faulty permission settings, and unexpected formatting error are all likely to cause your external hard drive to show up as 'Read Only' on your Mac. Luckily, there are solutions to these problems, either by formatting the device, changing settings, or repairing your device. Besides, if you get your data lost during the problem-solving process, you can retrieve your data with EaseUS Data Recovery Wizard. Try these tips without worries!

Don't worry when your external hard drive displays as read-only on Mac. This page includes 3 reliable solutions that can assist you in removing the 'read-only' error from your external hard drive, making it readable again on Mac. Pick up any method below to make your device accessible without losing any data now:

Workable SolutionsStep-by-step Troubleshooting
Fix 1. Reformat External Hard DriveOpen 'Applications' > 'Utilities' > Launch 'Disk Utility' to 'Erase' external drive > Restore formatted data...Full steps
Fix 2. Ignore PermissionsRight-click external drive > 'Get Info' > 'Sharing & Permissions' > Check 'Ignore ownership on...'...Full steps
Fix 3. Repair Drive ErrorsOpen Disk Utility > Select the external hard drive and click 'First Aid' > Click 'Run'...Full steps

SymptomsThe External Hard Drive Shows Up as 'Read Only' on Mac, Help!

'Hi there, do you know how to make the external hard drive accessible again when it shows as 'Read Only' on Mac computer? I'm having this problem that my Seagate external hard drive suddenly turned to read-only this morning when I connected it to Mac. I could only read and view saved data on the drive. But get no access to use the data on my external hard drive. If you have any clues to get permissions to access the read-only external hard drive on Mac, please tell me. Thanks very much.'

HardExternal Disk For Mac

If you right-click your external storage device, select 'Get Info', and see 'You can only read' at the bottom of the info window, you are encountering one of the commonest problems with an external hard drive. When your external hard drive or other external storage devices show up as 'Read Only' on your Mac, you can:

  • Open the drive and view the files
  • copy files from the external storage drive

You can't:

  • Copy files to the device
  • Delete files from the external drive

When you can't use your external storage devices normally, it could be quite annoying and frustrating for the problem not only represents a threat to your work efficiency but also shows the possibility of data loss.

ReasonsWhy Is Your External Hard Drive Read-Only on Mac

Why can you only read the external hard drive that is connected to your Mac? There are three possible reasons.

The File System Is NTFS

Right-click your hard disk and select 'Get Info'. If you find your external hard drive is NTFS format, that's what the cause is. The incompatibility of the file system is the main cause of the error-external hard drive 'Read Only' on Mac. NTFS is a file system that is optimal for Windows-based computer. Although the Mac operating system allows you to read the files on external hard drive, you can't write files to it because the way that NTFS writes data to the device is incompatible with the way of macOS doing it. (Go to the Fix.)

The Permission Settings Is Not Ignored

An external hard drive is subject to the access permission set up by OS X for all files and folders on the system. When you use the device on another computer with a different OS, the permission settings with it may not be recognized or prevent access to the files on the hard disk. (Go to the Fix.)

The Hard Drive has Formatting Errors

Another common cause for the external hard drive 'Read Only' problem on Mac is the formatting errors of the storage device itself. If you see a warning says the device is only being mounted in read-only mode while connecting, your hard disk is diagnosed to have formatting errors that prevent you from writing files to it. (Go to the Fix.)

Identify the cause that leads to the 'Read Only' error on your Mac from the information above, then follow the corresponding solution to solve the problem with ease.

FixesHow Can You Solve the External Hard Drive 'Read-only' Problem on Your Mac

Based on different reasons, there are three solutions to the problem.

Fix 1: Reformat the External Hard Drive

If your external hard drive is read-only on your Mac due to its NTFS file system, you can easily fix it by reformatting the device to a Mac-compatible format with the built-in Disk Utility on Mac. Before that, remember to back up your external hard drive quickly with a highly-efficient data backup software since the formatting will erase all the files on the device.

Step 1: Launch 'Disk Utility'.

  • Head to 'Applications' > 'Utilities'.
  • Or tap 'Command + Space' and type Disk Utility.

Step 2: In the list of available drives on the left, choose the problematic external hard drive. Then click the 'Erase' option in the main window.

Step 3: Choose a proper file system and rename your hard disk. (Both APFS and Mac OS Extended file system are Mac-exclusive. Thus, if you want your external hard drive to be both Mac and PC compatible, choose MS-DOS, also known as FAT, or ExFAT instead.)

Step 4: Click Erase to reformatting your external hard drive.

Wait for the reformatting process to complete and then go to the information window, this time you will see the 'You can only read' has changed to 'You can read and write', which means you can read and write the drive on your Mac normally.

Generally speaking, when a storage device shows up as read-only, you can still copy files off of it. If you cannot view or see all saved data on the drive, don't worry. After you format it, you can use the Professional Mac hard drive recovery software - EaseUS Data Recovery Wizard for Mac to get back your lost data on the drive with simple clicks:

Step 1. Select the disk location (it can be an internal HDD/SSD or a removable storage device) where you lost data and files. Click the 'Scan' button.

External Disk For Mac

Step 2. EaseUS Data Recovery Wizard for Mac will immediately scan your selected disk volume and display the scanning results on the left pane.

Step 3. In the scan results, select the file(s) and click the 'Recover Now' button to have them back.

Fix 2: Ignore Permissions

If you are sure the problem is caused by the permission settings, you just need to ignore the permissions to solve the 'Read Only' external hard drive problem on your Mac.

Step 1: Right-click your external hard drive shown on your Mac and select 'Get Info'.

Step 2: Expand the 'Sharing & Permissions' section, then click the lock to authenticate.

Step 3: Check 'Ignore ownership on this volume'.

Fix 3: Check and Repair Hard Drive errors

If there is formatting error on your external hard drive that makes the device read-only, you can use Disk Utility to check the errors and repair the external storage device.

Step 1: Go to 'Disk Utility'.

  • Head to 'Applications' > 'Utilities'.
  • Or tap 'Command + Space' and type Disk Utility.

Step 2: Highlight the read-only external hard drive, click 'First Aid' in the top center, then click 'Run'.

By default, your Mac starts up from its built-in hard disk, but a startup disk can be any storage device that contains an operating system compatible with your Mac. For example, if you install macOS on an internal or external drive, your Mac can recognize that drive as a startup disk. You can then follow the steps in this article to start up from it.

Use Startup Disk preferences

When you use Startup Disk preferences to select a startup disk, your Mac starts up from that disk until you choose a different one.

  1. Choose Apple menu  > System Preferences, then click Startup Disk.
  2. Click the lock and enter your administrator password.
  3. Select your startup disk, then restart your Mac.

If you see a message that your security settings do not allow this Mac to use an external startup disk, check the External Boot setting in Startup Security Utility.

Use Startup Manager

When you use Startup Manager to select a startup disk, your Mac starts up from that disk once, then returns to using the disk selected in Startup Disk preferences.

  1. Press and hold the Option (Alt) key immediately after turning on or restarting your Mac.
  2. Release the Option key when you see the Startup Manager window.
    If your Mac is protected by a firmware password, you can release the key when you're asked to enter the password.
  3. Select your startup disk, then click the arrow under its icon, or press Return.
    If you press and hold the Control key during this step, your selection is saved in Startup Disk preferences, so it persists until you change it.

If your Mac is using OS X Lion 10.7.3 or later, you can also use this method to start up from your Time Machine backup disk. Startup Manager identifies your Time Machine backup as ”EFI Boot.”

If you can't select your startup disk or start up from it

Check for these possibilities if you can't see your disk in Startup Disk preferences or Startup Manager, or your Mac won't start up from it.

Check for a compatible operating system on the startup disk

Make sure that your startup disk is using a version of macOS that is compatible with your Mac. If in doubt, use the same Mac to reinstall macOS on that disk.

To start up from an external disk with macOS Catalina 10.15 or later, the disk must connect via USB-A, USB-C, or Thunderbolt, not FireWire.

Check startup security settings

If you're using a Mac that has the Apple T2 Security Chip, check the settings in Startup Security Utility. These settings determine whether your Mac can start up from another disk.

Check for Option ROM firmware

If you're in Startup Manager and can't see a third-party startup disk, the startup disk could be using Option ROM firmware. To enhance system security, Mac computers with up-to-date software don’t show devices that use Option ROM firmware until you load their firmware. To do that, press Option-Shift-Command-Period while in Startup Manager. If your startup disk appears, do that each time you want to start up from it or from another disk connected to it.

Best External Disk For Mac

If you're using a firmware password, the ability to load Option ROM firmware is disabled as an additional security protection.