Recover Lost Data from External Hard Drive on Mac

Losing files on an external drive is stressful, but macOS includes built-in tools that can often recover deleted data or repair a drive that won’t mount. This guide walks you through the recovery process step by step, from checking the Trash to using Terminal commands, and explains what to do if your drive is physically failing.

What You’ll Need

Your external hard drive (connected via USB, Thunderbolt, or FireWire)
A Mac with a free USB/Thunderbolt port
A second external drive or enough free space on your Mac’s internal drive to store recovered files
Optional: a different cable or another Mac to test with

Step-by-Step

Stop using the drive immediately. If you deleted files by accident or the drive is showing errors, do not write any new data to it. New writes can overwrite the space where your deleted files still reside, making recovery impossible.
Check the Trash. If you deleted files from the external drive, they may be in the Trash. Open the Trash from the Dock, look for your files, right-click them, and select Put Back. If the Trash is empty, move on.
Unmount and remount the drive. If the drive is not showing up in Finder, open Disk Utility (in Applications/Utilities). Select the drive in the sidebar, click the eject icon, then unplug the drive, wait 10 seconds, and plug it back in. See if it appears on the desktop or in Finder.
Run First Aid in Disk Utility. If the drive mounts but behaves oddly (files missing, errors when copying), open Disk Utility, select the drive (not the volume below it), and click First Aid. Click Run and let it complete. This checks and repairs the file system structure, which can make hidden files reappear.
Check if the drive is visible in Disk Utility but not on the desktop. If the drive appears in Disk Utility but not in Finder, it may be unmounted. Select the volume (the indented item under the drive) and click the Mount button. If it mounts, your files should be accessible.
Use Time Machine if you had backups. If you use Time Machine, connect your backup drive, open Time Machine from the menu bar, and browse to the date before the files went missing. Select the files and click Restore.
Try Terminal commands for hidden files. Open Terminal (in Applications/Utilities) and type defaults write com.apple.finder AppleShowAllFiles YES then press Return. Restart Finder by holding Option and right-clicking the Finder icon in the Dock, then selecting Relaunch. This shows hidden files, which may include your data if the directory got corrupted.
Use a data recovery tool. If the above steps fail, you need specialized software. Download a reputable recovery app (such as Disk Drill, PhotoRec, or EaseUS Data Recovery). Install it on your Mac’s internal drive, not the external drive. Run the app, select the external drive, and scan for lost files. The scan may take hours, depending on drive size. Preview found files and recover them to a different drive.
If the drive is making clicking noises or not spinning up, stop all software attempts. These are signs of physical failure. Power off the drive and consult a professional data recovery service. Do not open the drive yourself—it requires a cleanroom environment.

Common Mistakes

Continuing to use the drive after data loss. Every new file written can overwrite the deleted data. Stop immediately.
Installing recovery software on the same drive. This writes new data to the drive, reducing recovery chances. Always install to a different drive.
Saving recovered files back to the same external drive. This can overwrite other lost files. Save to a different location.
Ignoring physical symptoms. If the drive is clicking, buzzing, or not spinning, software recovery attempts can cause further damage.
Formatting the drive to “fix” it. Formatting erases all data and makes recovery much harder. Only format if you have a backup and are sure you don’t need the data.

Tips

Regularly back up your external drive. Use Time Machine or a cloud service to avoid future data loss.
Safely eject drives. Always eject your external drive before unplugging to prevent file system corruption.
Use a surge protector. Power surges can damage external drives. A surge protector adds a layer of safety.
Keep your Mac’s software up to date. macOS updates include fixes for file system bugs that can cause data loss.
If you must try recovery software, use the free trial first. Many paid tools offer limited free scans, letting you see if files are recoverable before paying.

Troubleshooting

Drive not appearing at all: Try a different USB port, a different cable, and another Mac. If it still doesn’t appear, the drive may be dead or have a failed enclosure. If the drive is under warranty, contact the manufacturer.

First Aid fails or reports errors it can’t fix: This often indicates file system damage. Try running First Aid again after restarting your Mac in Safe Mode (hold Shift during startup). If it still fails, you may need to use a more advanced tool like fsck in Terminal, but this is risky and can cause data loss—consider professional help.

Recovery software finds files but they won’t open: The files may be corrupted or the recovery was incomplete. Try a different recovery tool, or recover to a different drive. If the files are important, a professional service may be able to extract more data.

Drive mounts but is read-only: This can happen if the drive is formatted with NTFS (Windows) and macOS can’t write to it. Your files are safe, but you can’t modify them. Use a third-party NTFS driver or copy files to a Mac-formatted drive.

You accidentally formatted the drive: Stop using it immediately. Recovery software can often restore files after a quick format, but the more you use the drive, the less likely recovery becomes.

Frequently Asked Questions

Q: Can I recover files from a dead external hard drive?
A: If the drive doesn’t spin up or makes clicking noises, it’s likely physically damaged. Professional data recovery services may be able to recover data, but it can be expensive. Do not attempt to open the drive yourself.

Q: How long does data recovery take?
A: It depends on the drive size and the method. Software scans can take from a few minutes to several hours. Professional recovery can take days or weeks.

Q: Is it safe to use free data recovery software?
A: Some free tools are safe and effective, but be cautious about downloading from unknown sources. Stick to well-known apps like PhotoRec or the free trial of reputable paid software.

Q: Can I recover files after I’ve emptied the Trash?
A: Yes, if the drive hasn’t been overwritten with new data. Recovery software can often find deleted files even after the Trash is emptied.

Q: Does Time Machine back up external drives?
A: By default, Time Machine backs up your internal drive. You can add external drives to Time Machine’s backup list, but it’s not automatic. Check your Time Machine settings.

Q: What should I do if recovery software can’t find my files?
A: Try a different recovery tool, or consider professional data recovery. If the files are critical, stop using the drive and consult an expert.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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