How to Fix The Disk You Attached Was Not Readable by This Computer Error on Mac

It’s one of those days when you attach your external drive to your Mac only to receive an error such as ‘the disk you attached was not readable by this computer.’ This would make you anxious especially when you think about the crucial files that lie within your external drive. 

Do not worry as this is a familiar problem that many Mac users face. That’s why we bring you a complete guide that’ll teach you where to start to fix a malfunction such as ‘disk is not readable by this computer’ on Mac. We’ll also disclose how to proceed further. So, let’s begin at once!

Part 1: Common Reasons Behind the Disk You Attached Was Not Readable Error

You might get ‘the disk you attached was not readable by this computer’ error when you link an external disk to it but are unable to access it. This issue could manifest because of numerous reasons such as:

1. Connection Problem – Broken USB cables or malfunctioning USB ports may stop your Mac from identifying an external drive.
2. Corrupted File System – A malfunctioning file system can make your external drive unreadable.
3. Unsupported File System – If your external drive is only formatted with a file system that supports only Windows, your Mac won’t identify it.
4. Uninitialized Disk – The disk might not be set up properly.
5. macOS Issues – Outdated software or bugs can cause drive access problems.
6. Virus Infections – Malware or viruses might cause your external disk to be unrecognized by Mac.
7. Damaged Disk – Symptoms of hardware damage such as dents, or scratches, or bad sectors can turn your external drive to inaccessible.

Part 2: How to Recover Data From an Unreadable Drive on Mac?

When an error such as ‘disk is not readable by this computer’ manifests on Mac, first, extract your data from the problematic drive. This is because when you’ll try to fix this malfunction later on, possibly with formatting, it would result in losing your files permanently. 

This is especially true if your external disk is already failing or severely corrupted. You can retrieve files with help of a specialized Mac data recovery software. One such tool is 4DDiG Mac Data Recovery is an excellent option for reclaiming files from unreadable external drives. Here’s what this tool offers to do:

• Reclaim files from drives that are undetectable, unreadable or inaccessible.
• Retrieve files lost due to various data loss situations e.g. corruption, virus attacks, lost partitions, crashed systems, deletion, formatting, and so forth.
• Regain files from various external devices such as disks, USBs, SD cards, etc.
• You can preview recovered files for free based on their path or type.
• It supports latest macOS Sequoia, and T2 and M series chips.
• No technical background required.

Following are steps to retrieve data with help of this tool from an external drive with ‘the disk you attached was not readable’ error on Mac:

Step 1: First, connect your problematic external to your Mac. Then, execute Mac Data Recovery tool on same Mac. Choose your drive, pick file types to scan, and hit “Scan.”

Step 2: You can pause or stop tool mid-scan to preview reclaimed files. 

Step 3: Once satisfied, click “Recover” to export reclaimed files to your computer.

Part 3: How Do I Fix ‘the Disk You Attached Was Not Readable by This Computer’ Error?

To fix ‘the disk you attached was not readable’ error on your Mac, you’ll need to perform some basic checks first. Most times, these simple steps can get rid of a malfunction such as ‘disk is not readable by this computer’ on Mac. If they won’t help, you can head to the next solutions:

Way 1. Perform Basic Checks

If you receive a ‘disk not readable’ on Mac error, it usually points to issues with your external disk, its connection, or your Mac’s system. Here are steps to fix it:

A. Reconnect the Device

Make certain the connecting cable is securely attached to both your external disk and your Mac. You can unplug and replug cable to be sure that the connection is good. 

B. Change Another USB Port

Some USB ports may not provide enough power or have data transfer limits. So, use a different USB port on your Mac. If you’re using a USB hub, connect external disk directly to your Mac.

C. Test on Another Computer

Attach your external disk to another computer to check if issue is with your drive or your Mac.

D. Initialize the Drive

If other solutions don’t work, initialize your external drive. To do this, open Disk Utility. Then, pick your external drive. Head to “Erase” tab. Pick a format like APFS for Mac.

E. Check if the Disk Is Encrypted

If your external disk is encrypted, you’ll need the correct password to access it. Some encrypted drives may require specific software to unlock.

F. Reboot Your Mac

Your Mac itself might suffer from some minor software glitches which could lead to a ‘flash drive not readable’ on Mac issue. This could be fixed by rebooting your computer.

Way 2. Check for File System Issues

Your external disk might be formatted with a file system e.g. NTFS or ReFS which is not supported by Mac. This could result in a ‘disk not readable’ on Mac error. So, what you can do is reformat your external drive’s file system to a compatible one suitable for your Mac. Here’s how to do that:

Step 1: Open “Disk Utility.” Do this via “Spotlight.”

Step 2: Then, select your unreadable external disk. Hit “Erase.” Next, pic a macOS-compatible file system e.g. exFAT. Then, hit “Erase” again.

Way 3. Update Your macOS

An outdated macOS could also cause a malfunction such as ‘flash drive not readable’ on Mac. This is because it lacks security patches and bug fixes that come with an update. Here’s how to update your macOS manually:

Step 1: Open “Apple” menu. Pick “System Settings.” 

Step 2: Then, move down. Next, pick “Software Update.” Install updates. Then, click “Restart Now” when asked.

Way 4. Run First Aid on the Unreadable Disk

In case, updating macOS won’t fix ‘the disk you attached was not readable’ error, then execute First Aid. It’s a built-in utility that locates and resolves disk-related errors such as ‘SD card not readable’ on Mac. Here’s how to execute First Aid:

Step 1: Open “Disk Utility.” Do this via “Spotlight.”

Step 2: Choose your unreadable external disk. Then, pick “First Aid.” Tap “Run.” It will fix the error.

Bottom Line

Getting a message saying, ‘the disk you attached was not readable by this computer’ on Mac can make you panic but you can work it out on Mac. If you follow steps provided in complete guide above you will be able to fix your unreadable external disk and obtain access to it successfully. 

However, before you apply any solution it would be wise to extract all data from your unreadable drive with aid of a specialized tool such as 4DDiG Mac Data Recovery. This is to save it from permanent file loss. This powerful software can rescue files from various data loss scenarios and external drives with a high success rate.