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Mac can't read APFS-encrypted external HDD on macOS Mojave

I upgraded my Mac and chose to use the new APFS file system on my external HDD. To make things go faster, I transferred 2TB of data from the old HDD to the new one, reformatted the old one with encrypted APFS, and moved the files back. Everything worked fine for a while until I received the message "Mac can't read the HDD, please use First Aid to fix it." Up until that point, the HDD had not been touched in any way—no sectors, partitions, etc.—until I tried TestDisk 7.2 WIP. It found a partition that looked like the lost one, selected it to recover, and then, boom, the restored partition emerged as a 2TB FAT32 partition and an empty one! Because the drive included the most recent photo data that was scheduled to be moved to the second HDD, the work is extremely important. However...

Best Answered by

Amanda Wong

Answered on Tuesday, August 27, 2024

In most cases, a corrupted external hard disk or maybe bad connections are the reasons why a Mac won't detect it. Nevertheless, there are further reasons why your Mac can't your external hard disk. When the external hard drive fails, it could become inaccessible, and all of the drive data is at risk.

When the APFS-encrypted external hard drive becomes unreadable suddenly on your Mac running macOS Mojave, you can try the following methods to fix unreadable drive on Mac:

Method 1. Check the connection issues and reconnect it.

Method 2. Run Disk Utility First Aid to check and repair the unreadable disk.

Method 3. Repair corrupted external hard drive on Mac with FSCK command.

Method 4. Recover data with data recovery software and then reformat the disk to repair the unreadable disk. If the TestDisk fails, you can try another professional data recovery software such as iBoysoft Data Recovery for Mac to scan the APFS-encrypted external HDD. Then you can reformat the drive without losing data.

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