How to Recover Data from an Undetected External Hard Drive on a Mac

Have you ever encountered the frustrating situation where your Mac doesn’t recognize your external hard drive? Don’t worry; there are ways to recover files from an undetected external hard drive. Here’s a comprehensive guide on how to recover data and prevent the issue from recurring.

Why Is My External Hard Drive Undetectable on My Mac?

External hard drives are typically reliable, but they can still encounter issues due to their moving parts and sensitive components. If your Mac cannot detect your external hard drive, there could be several reasons:

Common Reasons for an Undetected HDD

1. Outdated Hard Drive: Older drives may have configurations incompatible with your Mac’s new software.
2. Hard Drive Corruption: Corrupted drives may not be recognized by your Mac.
3. Interrupted Write Processes: Improper ejection can interrupt write processes and corrupt the drive.
4. No Drive Letter: Drives without a drive letter cannot be accessed by your Mac.
5. Connection Issues: Loose or faulty connections can prevent your Mac from recognizing the drive.
6. Hardware Damage: Physical damage can cause software issues that prevent recognition.

To rule out Mac-related issues, try connecting your external hard drive to another device. If other devices can read it, the problem likely lies with your Mac.

Initial Step: Check Disk Utility

Before attempting data recovery, check if the drive is visible in Disk Utility, a built-in macOS tool for managing storage devices. This can help you understand the issue and decide the best course of action.

Steps to Check Disk Utility

1. Open Disk Utility from the Applications > Utilities folder.
2. If your hard drive is visible in Disk Utility, select it and check its status.
3. If it says “This device is working properly,” the drive is functioning correctly.

If the drive is labeled as “Offline,” “Unallocated,” “Unknown/Not Initialized,” or lacks a drive letter, proceed with the following data recovery solutions.

Recovering Files from an External Hard Drive Visible in Disk Utility

1. Use Stellar Data Recovery Software

If your drive appears in Disk Utility, use reliable data recovery software for Mac like Stellar Data Recovery to retrieve your data. The latest version includes features like Duplicate File Finder, Mac Speed Up, and Large File Finder.

Steps to Use Stellar Data Recovery:

1. Download, install, and launch Stellar Data Recovery on your Mac.
2. The software will list all available storage devices.
3. Choose the external hard drive and click Scan.
   
   

4. Wait for the scan to complete.
5. Preview and recover the desired files.
   
   

2. Change the Offline Hard Drive to Online

1. In Disk Utility, find the offline hard drive in the list.
2. Select it and click Mount from the toolbar.
3. You may need to initialize or assign a drive letter if it’s not automatically assigned.

3. Fix Unallocated Space

1. Select the unallocated space in Disk Utility.
2. Click Partition in the toolbar.
3. Follow the instructions to create a new partition.

4. Fix Not Initialized/Unknown Drive

1. Select the uninitialized hard drive in Disk Utility.
2. Click Erase to initialize the disk.
3. Choose between APFS or Mac OS Extended (Journaled) for the file system.
4. Click Erase.

5. Change/Assign Drive Letter

1. Select the drive in Disk Utility.
2. Click Mount to assign a drive letter.

6. Reinstall USB Controllers

1. Open System Preferences and go to Software Update.
2. Ensure your macOS and drivers are up to date.
3. Restart your Mac and check if the drive is detected.

7. Fix Drive Errors with Disk Utility

1. Open Disk Utility.
   
   
   
2. Select the external hard drive.
3. Click First Aid to check for and repair errors.

8. Format the External HDD

1. Select the drive in Disk Utility.
2. Click Erase.
3. Choose APFS or Mac OS Extended (Journaled) for the file system.
4. Click Erase.

Recovering Files from an External Hard Drive Not Visible at All

1. Use a Different USB Cable or Port

Loose connections can prevent your Mac from recognizing your hard drive. Use a different cable and clean the ports on both your Mac and the drive.

2. Update Drivers for External Devices

1. Open System Preferences and go to Software Update.
2. Ensure your macOS and drivers are up to date.

3. Find a Data Recovery Service

If all else fails, consider professional data recovery services. These services have advanced tools to retrieve data from even severely damaged drives.

Conclusion

Experiencing issues with your external hard drive can be incredibly frustrating, especially when it goes undetected by your Mac. However, understanding the potential causes and following a systematic approach to troubleshooting can often resolve the problem. Start by ensuring your connections are secure and checking for the drive in Disk Utility. If the drive is visible, use Stellar Data Recovery software to retrieve your important files, leveraging its advanced data recovery features.

If the drive is not visible, consider other solutions such as changing the USB cable or port, updating drivers, or using professional data recovery services if necessary. These steps not only help in recovering your data but also address the underlying issues, ensuring that your drive remains functional in the future.