Why can't my Mac read the attached disk?

Data Recovery
1

After connecting an external hard drive to my Mac, I received a message that the disk was not readable by the computer. I need help understanding why this is happening and what I can do to fix the issue. Any advice or solutions would be appreciated.

4

If you’re getting a “disk not readable” message when connecting your external hard drive to your Mac, it’s often an issue with the drive’s formatting, file system compatibility, or potential disk corruption. Let’s break it down step by step:

  1. Check Disk Format: macOS supports several file systems, but if your disk is formatted in a file system that macOS doesn’t support natively (like NTFS for Windows), your Mac might not be able to read it.

    How to check:

    • Go to Applications > Utilities > Disk Utility.
    • Select the external disk from the left sidebar.
    • Look at the information in the main window. It will tell you the format (e.g., NTFS, FAT32, HFS+, etc.).

    If it’s NTFS, macOS can only read, not write to it without third-party software. FAT32 and exFAT are readable and writable on both macOS and Windows.

  2. Disk Utility First-Aid: Sometimes, a disk might have minor issues that can be fixed with Disk Utility’s First Aid feature.

    Steps:

    • Open Disk Utility.
    • Select the problematic disk.
    • Click First Aid at the top.
    • Follow the on-screen instructions.

  3. Reformatting the Drive: If the drive has severe issues or is in an incompatible format and you don’t need the data on it anymore, you could reformat it.

    NOTE: This will erase all data on the disk.

    To format:

    • In Disk Utility, select the external disk.
    • Click Erase.
    • Choose a compatible format (HFS+ or APFS for Mac-only usage, exFAT for Mac and Windows compatibility).
    • Name your drive and hit Erase.

  4. Data Recovery & Repair Tools: If the above steps don’t help, or if you need data from the disk before reformatting, you might need a more robust tool to help with data recovery and repair.

    One highly recommended tool is Disk Drill for Mac. Disk Drill can recover data from corrupted drives and even help with simple repairs. You can download it from Disk Drill (Mac). This software is handy because it supports multiple file systems and can handle complex recovery tasks.

  5. Check the Hardware: Ensure there’s no physical damage to the drive or its cables. Try connecting the drive to another USB port or another computer to see if the issue persists. If it works on another machine, the problem might be with your Mac’s USB port or its disk reading capabilities.

  6. macOS Updates: Sometimes, macOS updates could cause compatibility issues with external drives. Make sure your macOS is up-to-date.

    To check for updates:

    • Go to System Preferences > Software Update.
    • Install any available updates, then restart your Mac and try connecting the drive again.

  7. Terminal Check: If you’re comfortable using Terminal, you can check if your disk is recognized by the system:

    Steps:

    • Open Terminal.
    • Type diskutil list and press Enter.
    • This command will list all connected drives. Look for your external drive in this list. If it appears here but not in Finder, it’s likely a formatting or corruption issue.

If none of these steps resolve the issue, you might be facing a hardware failure of the drive itself. In such cases, contacting the drive manufacturer for support or considering professional data recovery services might be necessary.

Remember, using tools like Disk Drill can be a lifesaver before taking drastic measures like a reformat. They offer user-friendly interfaces and potent recovery mechanisms that could save your valuable data before you decide to proceed with a potential disk wipe.

3

First off, check if your external hard drive is compatible with Mac’s file system. Macs natively use HFS+ but can also read and write exFAT, and FAT32 without issues. However, NTFS, commonly used by Windows, is read-only on macOS unless you install third-party software like Paragon NTFS. If your drive is NTFS formatted, that might be a problem.

You could try connecting the external drive to another computer to see if it works there, just in case it’s a hardware issue. Also, make sure your macOS is up-to-date.

Disk Utility can be a lifesaver here. Open that up (you can find it in Applications > Utilities) and see if your disk shows up there. If it does, you might need to reformat the disk. Yes, this will erase all data, so back up anything important. To reformat, select the disk, click “Erase,” choose a format like ExFAT or Mac OS Extended (Journaled), and hit “Erase.”

If you need to recover data before reformatting, consider using Disk Drill for Mac. It’s decent for data recovery, and their YouTube channel (Data Recovery Videos on Youtube - https://www.youtube.com/@cleverfiles) has tutorials.

Disk Drill Screenshot
Disk Drill Soft1536×902 240 KB

One more thing, try using another USB port or cable to rule out that it’s not just a connectivity issue. Sometimes the obvious stuff gets overlooked!

Let me know how it goes or if you need more help.

2

Maybe your Mac doesn’t like cheap external drives. Nah, just kidding (or not). The problem could be that the drive is formatted in a way that Mac can’t read, like NTFS, which is common for Windows. Macs can read NTFS but they can’t write to it without special programs. Also, there’s a chance the drive is just corrupted or damaged.

You could try using “Disk Utility” on your Mac to see if you can reformat it, but this will erase everything on it. If you need the data on that drive, try a data recovery tool like Disk Drill for Mac. But be aware that Disk Drill isn’t free, and recovery might not be 100% guaranteed. Could be a total waste of time and money.

Disk Drill Screenshot
Disk Drill Soft1536×902 207 KB