“I connected my external disk to my Mac today and came across an error displaying that it is unreadable. It was accessible a few days ago and I haven’t used it on any other device. So, why is my USB/hard disk not readable on Mac now?”
____A Question from Reddit
The ‘the disk you inserted was not readable by this computer’ error on Mac is a distressing experience especially if the disk showed perfect readability previously. The situation becomes even worse when you realize your important files are stuck inside the device.
So, your main goal must be to reclaim them minus the data loss.
In this guide, I will tell you exactly how to extract your files safely from an unreadable disk along with some basic to advanced strategies to make your disk operational.
Let’s start!
Overview of ‘the Disk You Inserted Was Not Readable by This Computer’ Error
The ‘the disk you inserted was not readable by this computer’ error can appear on multiple storage devices like external hard drives, USBs, SD cards, etc. On a Mac, this means your system can’t read or access the device.
This issue could manifest with many signs, such as the following:
Signs
- A pop-up appears saying the disk is not readable.
- The drive doesn’t show in Finder or Disk Utility.
- Options like Initialize, Eject, or Ignore don’t fix the problem.
Causes
After seeing the signs, if you’re thinking about ‘Why is my USB/hard disk not readable on Mac’ this could happen due to numerous reasons like:
- The drive may use a Windows file system like NTFS, which macOS can’t read.
- A damaged file system or corrupted data can make the drive unreadable.
- Faulty wires, ports, or the drive itself may prevent connection.
- A password is needed if the drive is encrypted.
- Removing the drive abruptly can cause file system damage.
- Viruses may disrupt the drive’s function, making it unreadable.
How to Recover Data From an Unreadable Hard Drive?
When you receive an error such as the ‘disk is not readable by this computer’ on Mac, your first priority should be to extract your crucial data. This is because you might have to use advanced troubleshooting solutions which might include formatting to fix this issue.
So, lest you lose all files on your device, consider a professional Mac data recovery tool to extract all data from your unreadable disk. 4DDiG Mac Data Recovery app is an excellent option for retrieving files regardless of whether the disk is corrupted, unreadable, formatted, unbootable, inaccessible, etc. Here’s how this app can benefit you:
- This software supports a wide range of external devices like USBs, SD cards, and hard disks from popular manufacturers.
- It can reclaim 2000+ file types, including photos, documents, videos, and more.
- High success rate and fast scanning speed.
- This recovery tool provides a beginner-friendly experience.
- Supports the latest macOS 15 and macOS Sequoia.
Following are instructions to use this Mac recovery tool to extract data from your USB/hard disk that’s not readable on Mac:
Step 1: Install the Mac data recovery tool on your computer. Then, connect your unreadable drive to the same Mac. Choose it on the tool’s interface.
Step 2: Pick the file formats you wish to extract. Then, hit “Scan.” Once you find your desired files, stop the scan. Examine the recovered files by their path or name.
Step 3: Hit “Recover” to shift the files you’ve extracted to either your computer or cloud drive.
Quick Fixes for ‘the Disk You Inserted Was Not Readable by This Computer’ Error
Most times, you don’t need to apply any advanced solutions to fix the ‘the disk you attached was not readable’ issue on Mac. Only some basic checks such as examining the connection or file system can resolve this glitch.
Below are 4 quick fixes to resolve an error like the ‘USB/hard disk not readable’ on Mac:
Fix 1: Check the Connection
A loose or faulty USB wire or port could be the cause of a malfunction such as the ‘disk is not readable by this computer’ on Mac. So, examine the drive’s connector and your Mac’s ports for damage or debris as even dust or a bent connector can cause issues. Also, plug the drive into a different USB port, or use another wire. If it doesn’t function, connect it to another computer to rule out the issue with your Mac.
Fix 2: Check for the Encrypted Drive
Your drive might be encrypted that’s why you might be receiving the ‘the disk you attached was not readable’ error. So to make it readable again you’ll have to decrypt it. But first, follow steps below to examine whether your disk is encrypted or not:
Step 1: Plug in your external drive to your Mac. Then, open “Applications.”
Step 2: Open “Utilities.” Next, click “Disk Utility.” Select your unreadable drive from the sidebar.
Step 3: Then, examine the disk’s encryption status. If it’s encrypted, you’ll need the software you used to encrypt it to access its contents.
Fix 3: Check the File System of the Device
It could be that your disk is formatted to a Windows-compatible file system such as NTFS. That’s why your USB/hard disk is not readable on Mac. Here’s how you can examine the file system of your unreadable disk:
Step 1: Connect your unreadable disk to your Mac. Then, open “Finder.”
Step 2: Right-click the disk in the “Finder” bar. Next, pick “Get Info.” You’ll learn the file system to which your disk is formatted.
Fix 4: Update the Disk Driver
An outdated external disk driver could lead to the ‘the disk is not readable by this computer’ on Mac glitch. This is because it doesn’t have the crucial bugs and security patches required to run an external drive. However, on Mac, you can’t update drivers only but will have to update the entire macOS. Here’s how to fix unreadable USB flash drive on Macbook by updating the disk driver:
Step 1: Choose “System Preferences” from the menu. Then, tap “Software Update.”
Step 2: Look for any available updates. Install them.
Advanced Troubleshooting Methods for ‘Disk Is Not Readable by This Computer’ Mac Error
In a situation where you’re unable to fix ‘the disk you attached was not readable’ malfunction proceed to solutions such as using First Aid and disk initialization. Here we’ve explained them in detail:
Fix 1: Use First Aid
If your external drive is unreadable execute First Aid. It’s a macOS-embedded tool that can repair file system and directory structure issues in internal/external disks. Here’s how to fix unreadable USB flash drive on Mac by using First Aid:
Step 1: Plug in your external drive to your Mac. Then, open “Applications.”
Step 2: Open “Utilities.” Next, click “Disk Utility.” After this, tap “First Aid” on the menu up top.
Step 3: Hit “Run” to execute First Aid to repair your unreadable external disk.
Fix 2: Initialize the Disk
Still wondering, “Why is my USB/hard disk not readable on Mac?” This is because your drive’s Master Boot Record (MBR), that helps the system detect partitions and file systems might be corrupted. To fix it you’ll need to initialize the unreadable drive. This will rebuild the MBR to resolve recognition and access issues.
Initialization also prepares new or unallocated disks for use. Afterward, you can create partitions to organize and use the disk properly. The Master Boot Record (MBR) stores partition information on a disk. Follow these steps to initialize the disk. Here’s how to fix unreadable USB flash drive on Mac by initializing your unreadable drive:
Step 1: Plug in your external drive to your Mac. Then, open “Applications.”
Step 2: Open “Utilities.” Next, click “Disk Utility.” After this, tap “Erase” on the menu up top.
Step 3: A new window will open. Pick a name, format, and scheme. Hit “Erase” again.
How to Avoid ‘the Disk You Inserted Was Not Readable by This Computer’ Error?
Only successfully resolving ‘the disk you inserted was not readable by this computer’ malfunction on your Mac isn’t enough. It’s time you also think about preventing this issue from popping up in the future. For this, you’ll have to take active steps such as we’ve mentioned beneath:
- Backup Data – Regularly back up important files from your external drives to your Mac or cloud to avoid data loss
- Eject Properly – Always eject drives before removing them from your Mac to prevent file system corruption.
- Monitor Health for – Examine your drive’s health closely to check any signs of failure or corruption.
- Update Software – Keep macOS updated for better file system compatibility.
- Use Compatible Formats – Always format drives as APFS or exFAT for macOS.
- Check Hardware – Examine US wires and ports for damage to prevent connection issues.
Bottom Line
The ‘the disk you inserted was not readable by this computer’ error on Mac can manifest due to connection problems, incompatible file systems, or more serious issues like drive corruption or a faulty MBR. However, your priority should be to extract data from your unreadable disk as you might have to initialize the disk later on which would result in data loss.
But you can’t reclaim files from an unreadable disk unless you take the help of a professional recovery tool. We recommend 4DDiG Mac Data Recovery which is a great tool to extract lost files from inaccessible and severely corrupted internal/external drives with high success.
