I have external hard drive which stored my back, one day it stopped work and then gave a red error message. I ran Disk Utility's Repair Disk and got the message that the external drive had an invalid node structure. Any ideas on how to fix external HDD invalid node structure error and recover data?
The invalid node structure error indicates that there is a very serious problem of the disk directory structure. Mac inbuilt Disk Utility may not be able to fix it. One method of fixing the problem is very simple: recover data, reformat the drive and then copy data back.
Recover data from corrupted external hard drive
To recover data from invalid node structure error, we need a professional Mac data recovery software. Here we strongly recommend M3 Mac Data Recovery, an easy-to-use Mac data recovery software which can recover deleted files even if emptied from Trash, recover data from formatted drive, recover data from deleted or lost partition, recover data from unreadable hard drive, recover data from corrupted external hard drive, etc. under macOS 10.13/10.12 and Mac OSX 10.11/10.10/10.9/10.8/10.7/10.6.
Tutorial to recover data from corrupted external hard drive
Step 1: Download, install and launch M3 Mac Data Recovery on your Mac computer.
Step 2: Select "In a specific volume:" and then select corrupted external hard drive volume from drop-down list.
Step 3: M3 Mac Data Recovery is scanning the data from corrupted external hard drive volume.
Step 4: Select the found files you expect to recover and then click Recover to save them.
Reformat the corrupted external hard drive
After data recovery is successfully done, please try the following method to reformat the corrupted external hard drive:
Step 1: Launch Disk Utility from Utilities.
Step 2: Click the icon for your external hard drive in the sidebar on the left.
Step 3: Click the Erase tab along the top of the window.
Step 4: From the Volume Format menu, choose Mac OS Extended (Journaled).
Step 5: Enter a name for the external hard drive in the Name field.
Step 6: Click the Erase button.
Copy data back
Once you reformat the corrupted external hard drive, you can copy the recovered data back to this external hard drive.