External disks such as external hard drive, thumb drives, and SD cards are frequently used as extended storage for digital devices or portable media for file sharing.
How Do I Make My Seagate Work With A Mac? One thing you should know first. Sudo mount -t hfsplus -o force,rw /dev/sdxy /media/mac where you would now access the folders on that drive in the /media/mac folder on the drive. Once in that folder you should be the contents of the Mac drive. If it is already mounted, try the following line to remount the drive: sudo mount -f hfsplus -o remount,force,rw /dev/sdc2 this is assuming that /dev/sdc2 is your Mac drive partition. Hope this helps! Have you ever tried to format a disk in Mac OS X and Disk Utility won't Unmount the Hard Drive for formatting? It can happen for external (USB and Firewire).
Using physical external disks will sometimes encounter unexpected situations. For example, when you connect an external disk to a Mac, the disk becomes readable but not writable.
The read-only state could result from limited file control, unsupported NTFS access or corrupted disk protection. We will look into each cause and illustrate detailed solutions.
If you know the cause, you can jump to the specific case and find the solutions. If not, read through the article to get the read-only disk problem resolved.
Case 1: You have read-only file privilege over the external disk
It happens often if you get the disk from another hand. The previous owner has set up read-only permission to this disk to protect data from unwanted changes.
If the read-only permission was set up by third-party software, you will need the same software to change the file permission. If the permission was set up on the Mac computer, follow the following steps to change read-only files on Mac.
- Step 1: Connect the external hard drive to the Mac and wait for it to be mounted on the desktop.
- Step 2: Right click the icon of the external disk and select Get Info.
- Step 3: Unfold Sharing & Permissions at the bottom. A message ' You can only read' will be shown underneath.
- Step 4: Click on the lock at the corner and input your user name and password.
- Step 5: Click the Read only under Privilege of your user name and select Read & Write.
- Step 6: Click on the lock to ensure the change.
If you are the administrator of this computer, you can also tick the box in front of 'Ignore ownership on this volume' and then input your admin password to be able to write to the external disk.
Case 2: macOS has read-only support to NTFS-formatted disks.
If the restrained file permission is not the cause, file system incompatibility could be the roadblock. Still in the Get Info window, under General information, you can see the Format is Windows NT File System.
NTFS is the proprietary file system by Microsoft and macOS only allows read-only access to NTFS. When using an external USB drives such as external hard drive, solid-state drive or thumb drive, you will find you can't store any files to it and existing files are locked or read-only.
To enable full NTFS read and write access, you can modify macOS kernel extension through commands. But it will become tedious because you need to do it every time you restart your computer.
Another one-for-all solution is to back up the current files and format the disk to FAT or exFAT. The drawback is that it is time-consuming especially when you have tons of data to back up.
We recommend you install free NTFS for Mac to read/write to a Windows NTFS drive.
- Step 1: Download iBoysoft NTFS for Mac or any other app you may be interested in.
- Step 2: Install the app and launch it following the onscreen wizard.
- Step 3: Read & write to NTFS-formatted disks freely if the disk is automatically mounted in read-write mode. If not, manually unmount and remount the disk by yourself.
Case 3: The external drive becomes read-only because it is corrupted.
Most times, when a disk is corrupted, the macOS is unable to mount it or shows 'the disk you inserted is not readable by this computer' error when it is plugged in.
It is rare that a corrupted disk still can be viewed as usual. However, in a certain scenario, the disk still can be mounted in read-only state to prevent data overwritten from any writing activities.
This could be a warning sign that your external storage device is failing. You should get hands on saving your files and fixing the corrupted disk.
- Step 1: Move your files to another destination to make sure they are safe before the disk completely stops working. If necessary, use professional data recovery software to restore important files.
- Step 2: Open Disk Utility and find the disk on the right sidebar. Disk Utility can be found in Applications folder in Finder.
- Step 3: Right-click on the disk and select Run First Aid.
- Step 4: Eject the disk safely and reconnect it to the Mac if the disk still can't be mounted to be editable.
First Aid can only fix minor software errors on a storage medium, so big chances are that it may fail to fix the read-only disk.
To remove all errors, you can format the disk in Disk Utility using Erase option with an adequate backup first.
Conclusion
When external hard drives, SD cards, or USB flash drives suddenly became read-only, don't panic. The problem is totally solvable with free and easy solutions.
We want to remind you again, formatting the disk to get rid of NTFS file system or repair the corrupted file system will delete all files on the portable disk, so remember to back up files first when conducting erase option.
Related Posts
Mac or MacBook Doesn't Detect My External Drive. 7 Ways You Can Fix It!
An external hard drive is a lifesaver when you need a large amount of storage to store your files. What's great is that you can carry the drive with you wherever you go and easily move large files from one Mac to another. Due to large storage capacities, you can use your external hard drive as a storage backup for your Mac. You can use an external drive to set up Time Machine, which backups your personal data, including apps, photos, music, emails, and documents. External drives are very useful when expanding your Mac's existing storage. If you often see low disk space warning, it's best to transfer your files to an external hard drive from the internal drive as it will improve your Mac's performance.
The difference between internal and external drives is that the internal drive is connected directly to your Mac's motherboard, whereas an external drive is connected to the motherboard of your Mac from the outside to the with a cable. External hard drives are generally used for storing non-system files while internal drives store operating systems and software installation files. Although external drives are great for multiple reasons, the data stored inside can be compromised much easier than that in internal drives as it's easier to steal. While to steal data from an internal drive, the entire computer has to be taken, or it has to get infected with specific malware. External drives are also more prone to mechanical damage as they are generally moved around more.
Using an external hard drive is relatively easy as you just need to plug one end of the data cable into the drive and the other into your Mac. If the drive needs an additional power source, a power cable needs to be plugged into a wall socket. Usually, when you connect your drive to your Mac, an external drive icon appears on your desktop almost instantly. Then you can begin moving files back and forth.
Unfortunately, sometimes Macs and MacBooks can't recognize the external drive. That can happen when you eject the external drive the wrong way by unplugging it from your Mac without ejecting it. Then when you plug it back in suddenly, your Mac can't recognize the drive. To remove your drive in a safe way, first, you need to eject it from your Mac. Just right-click on your external drive icon and click on Eject Device. Only then remove it from your Mac externally.
The other reason can be your Mac's or your drives hubs not working. They might have accumulated dirt and dust or were mechanically damaged. In that case, you need to clean them or change them entirely.
This issue can also occur if you plug your drive to fast into the hub. Many users have stated that by slowly plugging the drive into the port resolves this issue. Try to plug your external drive into the port gently and see if your Mac detects it.
If the connecting cable was damaged, it could also be one of the reasons why your Mac doesn't detect the external drive. So check your cable, dongles (if used), and any additional adapters for damage. If your drive is recognized, but it randomly disconnects without any warning, that can mean frayed or worn cables, and it's time to change them.
Another reason can be if your drive is not receiving enough power from the port. If an additional power supply is available for your drive, plug it directly into a power source. If not, try connecting the drive to another USB hub.
If your Mac still doesn't detect the external drive, check whether it's a problem with your drive or Mac. To do that, plug the drive into another Mac. If the drive doesn't mount on the Mac, the problem is likely with your drive, and if it does mount, then the problem is potentially with your Mac.
Check below for more advanced troubleshooting steps.
Table of Contents:
- Method 1.Check Your Settings
- Method 2.Run Disk Utility
- Method 3.Reformat External Drive
- Method 4.Remount External Drive Using Terminal
- Method 5.Reset NVRAM
- Method 6.Reset SMC
- Method 7.Inspect The External Drive via Console
It is recommended to run a free scan with Malwarebytes - a tool to detect malware and fix computer errors. You will need to purchase the full version to remove infections and eliminate computer errors. Free trial available.
Check Your Settings
Before proceeding to more complex troubleshooting steps, check your settings if hard and external disks are set to be shown on the desktop.
1. Go to the upper menu and click on the 'Finder' menu.
2. Go to 'Preferences.'
3. In the 'General' tab under 'Show these items on the desktop', check the boxes next to 'Hard disk' and 'External disk.'
If the boxes are checked, and you don't see the external drive on your desktop, proceed to the next step.
Run Disk Utility
Go to Disk Utility and lookup if your external drive is visible there. Run First Aid to find the issue with your drive.
1. In the upper menu, click on the 'Go' menu and select 'Utility.'
2. In the Utility window, find and click on 'Disk utility.'
3. If you see your external drive in the Disk Utility window, but it shows that it's not mounted, select the drive and click on the 'Mount' button.
4. Then, go to the upper menu and click on the Apple logo.
5. Click on 'About This Mac.'
6. Go to the 'Storage' tab. If you can't see your external drive there, go back to the 'Disk Utility' window.
7. Select the drive and click on 'First Aid.'
8. Then click on 'Run' and wait for the process to finish.
The First Aid option will check the disk for errors and then repair the disk if necessary. Click on 'Repair Disk' if you see this option pop up.
Reformat External Drive
If you see your drive in the Disk Utility window but could not mount it to your Mac, you might have a disk format issue. In this case, you need to reformat the drive. PCs with Windows operating systems use the New Technology File System (NTFS). In contrast, Macs with macOS operating systems use the Hierarchical File System (HFS+). By default, USB flash drives and other external drives are formatted with the NTFS file system - this works great on PCs, while Macs can read data in the format but struggle to write it. Fortunately, you can format your external drive with the File Allocation Table (FAT32) or Extended File Allocation Table (ExFAT) file system.
Format FAT32 [on a Mac, known as MS-DOS (FAT)] is fully compatible with all versions of Windows and Mac operating systems. Therefore, even the oldest operating system versions such as Windows XP SP1 and OS x 10.5 Leopard are compatible. The FAT32 file system is also supported by Xbox 360, PlayStation 3, and most cameras. Unfortunately, this particular file system does have file size restrictions. The maximum size of supported files is 4GB which means you can't write files larger than 4GB. Also, you can't create a startup drive for Macs within storage media that uses the FAT32 file system. Suppose you are not planning to use external storage to transfer large files or create executable partitions (such as a Mac startup drive). In that case, the FAT32 format can be a great option.
ExFAT is a file system format that has an advantage over the FAT32 file system. It has no restrictions on file or partition sizes. Therefore, you can write a 1TB size file and create partitions of 5TB within the device. Despite the improved data size, some older versions of operating systems are no longer compatible with this file system format. The oldest versions of operating systems compatible with ExFAT are Mac OS X Snow Leopard 10.6.5 or later, OS X Lion, Windows XP SP2, or later (with an additional update for exFAT support, Windows Vista SP1 or later and Windows 7.
Unfortunately, the ExFAT file system format is not supported by various cameras, video game consoles, and other devices that are able to read and/or write to external storage. If you will be using a USB flash drive or external storage device with any of these devices, the required format is FAT32. If the drive is to be used only with computers with modern versions of operating systems, the recommended format is ExFAT.
Format external drive:
1. In the upper menu, click on the 'Go' menu and select 'Utility.'
2. In the Utility window, find and click on 'Disk utility.' In the Disk Utility window, select your drive.
3. Click on the 'Erase' option.
4. Choose the disk format as ExFAT, MS-DOS (FAT), or Mac OS Extended (Journaled).
5. Click on 'Erase.'
6. Then, go to the upper menu and click on the Apple logo.
7. Click on 'About This Mac.'
8. Go to the 'Storage' tab to see if your external drive is visible.
Remount External Drive Using Terminal
First, check if the system recognizes your drive. If it does see that the external drive is plugged into your Mac, but it doesn't show up, try to remount the drive using Terminal.
1. Then, go to the upper menu and click on the Apple logo.
2. Click on 'About This Mac.'
3. Go to the 'Storage' tab to see if your external drive is visible.
4. Open Spotlight by pressing Command + Space keys on your keyboard.
5. In the Spotlight, enter 'Terminal' to open it.
6. In the Terminal window, enter: diskutil list
The 'diskutil list' command will display the essential information about all available drives and volumes attached.
7. Then search for /dev/disk_ (external, physical). Make sure to remember the number following after the word 'disk.'
8. In the same Terminal window, enter another command line: diskutil info disk(digit)
9. After that, eject your disk by entering the command: diskutil eject disk(digit)
10. After executing the eject command, check if it was removed by entering the command line: diskutil list
If you don't see your drive in the list, that means you removed it successfully. Then remove the drive physically from your Mac.
Reset NVRAM
Nonvolatile Random Access Memory (NVRAM) stores hard drive information. If NVRAM has encountered bugs, your external drive not showing up can be the cause of it. In this case, it's best to reset NVRAM.
1. Restart your Mac.
2. When you hear the startup sound, simultaneously hold down Command + Option + P + R keys on your keyboard for 20 seconds.
3. When you hear the startup sound for the second time, you can let go of the keys.
If you have a newer Mac, you don't need to restart your Mac to reset NVRAM. Just hold down the keys for 20-30 seconds, and the NVRAM will be reset.
Reset SMC
Remount External Hard Drive Macbook Pro
If your Mac or MacBook shuts down after you connect your external drive, that means the drive consumes too much power from the USB port. If your drive can't connect to an additional power source and the issue keeps on repeating, try resetting SMC (System Management Controller).
If the battery is integrated:
1. Shut down your Mac.
2. Unplug all peripherals.
3. Simultaneously hold down Shift + Control + Option keys on your keyboard together with the Power button for 10 seconds. If you have a MacBook Pro the Touch ID button is also the power button.
4. Then reconnect your power cable and other devices.
5. Turn on your Mac.
If the battery is removable:
1. Shut down your Mac.
2. Unplug all peripherals and remove the battery.
3. Press and hold the Power button for 5 seconds.
4. Insert the battery and connect your Mac to the power source.
5. Turn on your Mac.
Remount External Hard Drive Mac
Inspect The External Drive via Console
The Console app can be handy in times of trouble. It displays log information that helps to troubleshoot problems on your Mac. It won't fix the problem but will provide information to diagnose the problem.
1. In the upper menu, click on the 'Go' menu and select 'Utility.'
2. In the Utility window, find and click on 'Console.'
3. Select the 'Error and Faults' tab.
4. Plug in your external drive to your Mac.
5. Then look to see if it detects your drive or if there's an error. If no errors pop un and nothing happens, then your problem is not with the external drive.
Let us know in the comments which solution helped you fix the problem!
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