Summary: This blog post shares methods to resolve the external hard drive ‘read-only’ error on Mac. These methods involve erasing the drive, ignoring ownership, and repairing the drive.
It further guides you on Mac external hard drive recovery solution, in case the data is deleted or erased while troubleshooting the external hard drive ‘read-only’ error.
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Imagine, after connecting an external hard drive to your Mac, you find that you can’t save any files or folders on the drive or delete data from it. Though you’re able to copy the stored data from the Mac external drive. You are baffled with this situation and need an immediate fix for the external hard drive read-only error on Mac.
Verify the Read-Only Status of an External Hard Drive on macOS
To know the status of your external hard drive, do the following:
- Connect your external hard drive to your Mac
- Right-click the drive either from the Desktop or Finder
- From the context menu, select ‘Get Info’
- Check the file system format of the drive
- From the bottom of the window, check whether it shows “You can only read” or “You can read and write”
If the drive is in read-only state, then you can only read data from the drive, but cannot write data on to it. So, what might be the reasons behind this read-only state? The following section describes in detail.
Reasons for an External Hard Drive ‘Read Only’ State
- Mismatched File System: If your external hard drive is in the NT File System (NTFS) format, then macOS treats the drive as read-only. NTFS is the proprietary file system of Windows and is not compatible with macOS.
- Permission Settings Issue: If your macOS could not recognize the access permission settings for your external hard drive, then the system will either prevent access or provide read-only permission to the external hard drive.
- Formatting Error: If the external hard drive is not erased correctly and has formatting errors, then macOS may mount the drive but may not allow writing data on to it.
How to Resolve Mac External Hard Drive Read-Only Error?
1. Erase the Drive
Warning: Back up the files on the Mac external hard drive before erasing it. This is critical to avoid data loss.
If the external hard drive is in NTFS format, erasing it to a macOS compatible file system format should fix the read-only issue.
Erase the external storage drive, as follows:
- Go to Finder > Applications > Utilities > Disk Utility
- Select the external drive from the sidebar and click the Erase tab
- On the pop-up dialog box, type the name of the formatting drive
- Select APFS or Mac OS Extended (Journaled) alongside the format option
- Click Format to initiate the formatting process
Once you have erased the external storage drive, you can connect the drive as usual to your Mac to read and write content on the drive. In case you wish to use the drive on both Windows and macOS system, then you must erase the drive in either exFAT or MS-DOS (FAT).
2. Ignore Ownership
When the read-only error is due to unrecognized access permission settings, then do the following:
- Right-click the storage drive, and from the context menu, opt ‘Get Info’
- Expand ‘Sharing & Permissions’ and click on the lock icon
- Provide the admin password
- Select ‘Ignore ownership on this volume’ checkbox
Ignoring the ownership may solve the read-only problem with the drive.
3. Repair the Drive
In case the Mac external drive has formatting errors, then do the following:
- Go to Finder > Applications > Utilities > Disk Utility
- Select the external drive from the sidebar and then click the First Aid tab
- Click Run. When the report is OK, click Show Details to know more about the repair. In case the report is ‘The underlying task reported failure’, try to repair the external drive again
Disk Utility will verify and repair hard drive errors and plausibly fix the read-only issue.
While troubleshooting the Read-Only error, there’s a possibility that you forgot to back up the data stored on the hard drive before erasing it or the backup doesn’t contain all the data.
In this situation, a Mac external hard drive data recovery software will help you retrieve the lost data from the erased hard drive. The following section outlines a data recovery software which helps in this particular situation.
Perform Mac External Hard Drive Recovery by Yourself
To recover erased or deleted data from the Mac external storage drive, go through the following steps:
When the software completes the recovery task, go to the specified save destination to verify the recovered data. Copy the data back to the external storage drive with macOS compatible formatting.
Video: Mac External Hard Drive Recovery Tutorial with Stellar Data Recovery Professional for Mac
The blog highlighted the case of Mac external hard drive read-only error, how to verify the error state, its causes, and how to fix the ‘read-only’ error.
For instance, when the external hard drive has a mismatched file system, then the best fix is to copy the content of the drive to your Mac, and then erase it by using Disk Utility. Once the drive is formatted to the macOS Mojave compatible format, you can restore the copied files from the Mac to the formatted external storage drive.
Further, if you are using the external hard drive on older Mac OS X system, then the newer macOS Mojave system may not recognize the access permission settings. So, you can try to ignore ownership of the drive to fix the read-only problem. When the drive has formatting errors, you can use Disk Utility’s First Aid to fix those errors.
While implementing these procedures, in case the data stored on the hard drive is lost and there’s no back, try a data recovery software such as Stellar Data Recovery Professional.
It supports macOS Big Sur, Catalina, Mojave, and APFS, and recovers data from all leading storage drive brands.