The Disk You Attached Was Not Readable by This Computer

“The disk you inserted was not readable by this computer" message means that your laptop failed to recognize your external hard drive or USB flash. This is usually because when the hard drive is either corrupted or inserted incorrectly, or when the file system is incompatible.

What does “The disk you attached was not readable by this computer” mean?

The notification “The disk you inserted was not readable by this computer" means your MacBook device doesn’t recognize your external hard drive, such as a flash stick or SD card. This can be caused by a corrupted hard drive, an incompatible hard drive, or even a loose or faulty connection.

Why does “The disk you attached was not readable by this computer” happen?

The common causes of a “The disk you attached was not readable by this computer” message include:

• Unsupported file systems that macOS can’t recognize or read
• Disk corruption is preventing the drive from mounting
• Faulty or loose connection cable
• Damaged or malfunctioning USB port
• Malware or virus infection
• Uninitialized or unformatted disk
• Encryption without the correct password or decryption key

A note from our experts: 

 

Though disk-related issues are no strangers to Mac devices, they may be new to some Mac users. If you’re unsure how to proceed, we recommend leveraging MacKeeper’s Premium Services. While we’ve listed detailed instructions below, MacKeeper’s Premium Services tool is a quicker and more professional way to troubleshoot unreadable disks and similar issues, rather than spending valuable time trying to figure it out yourself. MacKeeper is developed by Clario Tech and notarized by Apple, making it a reliable solution for managing your Mac.

 

Ready to fix your disk issues? Here’s how to use MacKeeper’s Premium Services software:

1. Download and install MacKeeper on your MacBook Pro or MacBook Air.
2. After installing the app, click on Premium Services and then press the big Chat Now button on the right side of the screen.
3. MacKeeper will quickly connect you with an expert technician. Explain the issue you’re experiencing in detail and follow their instructions.

Please note that you may have to grant the expert technician assisting you remote access to your laptop, so ensure you’re comfortable with that first. Granting the expert technician remote access to your MacBook allows them to access it so they can make an accurate assessment of the problem you’re facing by seeing it from your point of view. This allows them to properly assist you in fixing the error, as though you were doing it yourself, rather than providing you with instructions for what to do.

How to fix “The disk you attached was not readable by this computer” error

To fix the error that reads, “The disk you attached was not readable by this computer”, use First Aid in Mac’s Disk Utility app. Manually mount the drive you want to use. Then, use Terminal to check or repair the disk, though we only recommend using Mac’s Terminal app if you’re familiar with it to avoid making costly mistakes. Other options include using third-party recovery software and reformatting the disk.

Want to see how these fixes work in action? Follow the steps below to find out.

1. Use First Aid

First Aid helps to fix an unreadable disk by finding and repairing problems in its file system and directory structure, especially for corrupted or permission-related issues. This is what makes it our go-to solution for repairing a Mac disk with Disk Utility.

To use First Aid in Disk Utility, follow these steps:

1. Launch Disk Utility using Mac’s Finder or Spotlight search tool.
2. Find your disk on the list and select First Aid > Run.

2. Mount the drive manually

Mounting the drive manually can sometimes fix an error with a disk that won’t read by forcing the system to recognize the drive. This often works if the disk fails to connect to the operating system, rather than a physical issue.

Here’s how we mount the drive manually on a Mac:

1. Launch Disk Utility on your Mac.
2. Choose the volume you want to mount and click the Mount button.

3. Use Terminal to check or repair the disk

We sometimes use Terminal commands to check a disk that isn’t readable on a Mac. Due to the complexity involved, we recommend that you only use this method if you’re comfortable using Mac’s Terminal app and have backed up your files.

Here’s how to check or repair the disk in Terminal:

1. In the Terminal app, enter the command diskutil list and press Return to display all connected drives (don’t forget to make a note of your drive’s identifier).
2. Enter the command diskutil verifyDisk [identifier] (replace [identifier] with your drive’s identifier) and press Return.
3. If Terminal finds any issues, type diskutil repairDisk [identifier] (replace [identifier] with your identifier) to repair the disk.

4. Use third-party recovery software

Sometimes, Mac’s native solutions don’t yield the desired results. When this happens, we turn to third-party tools, which can attempt to recover personal data from the unreadable disk by scanning the damaged drive to find and extract files.

Here are a few recovery software options to consider. Make sure you research your chosen solution before installing it on your MacBook.

• Disk Drill
• UFS Explorer
• R-Studio

5. Reformat disk

Reformatting a disk creates a new, compatible file system for your Mac. Because it erases data, we always make sure we only use it as a last resort and try to either recover important data or access it from another laptop first.

Confident about reformatting your disk? Here’s how to do it:

1. In Disk Utility, right-click on the target disk and select Erase.
2. Preview the disk name and file system, and then press the Erase button.

When to seek professional data recovery

Still stuck with an unreadable external disk after trying all the solutions provided? It may be time to seek professional assistance. Set aside time to visit a certified Apple service provider or a trusted data recovery specialist if you’re encountering any of the scenarios below:

• Your Mac doesn’t detect the disk at all, even when you look for it in Disk Utility.
• Your Mac’s disk is either physically damaged or keeps making clicking, grinding, or beeping sounds.
• The disk contains critical files you simply can’t afford to lose. This can include anything from work documents to sensitive information such as financial records and personal photos.

“The disk you attached was not readable by this computer” Mac fix

Receiving a message saying “The disk you attached was not readable by this computer” can be alarming, given the risk of losing your data. Before you panic, consider trying the fixes in our helpful guide. Use First Aid in Disk Utility on Mac, manually mount the drive, or try Terminal to check or repair the disk. Alternatively, use third-party recovery software or simply reformat the problematic disk.

The simplest, time-saving solution is to leverage MacKeeper’s Premium Services. It puts you in touch with an experienced technical expert, who takes care of the error of your external drive not showing up on your Mac on your behalf.