无法挂载疑似损坏的1TB加密外接硬盘，如何擦除重置？

Hey there, let's work through this step by step to get your 1TB external drive back up and running properly.

Since your drive is encrypted and won't mount, we'll start with reliable, low-level steps to wipe all old data and partition info before reinitializing.

Step 1: Identify Your Target Disk (Critical—Don't Mess This Up!) #

First, make sure you're targeting the right drive (not your internal Mac disk):

• Open Terminal and run diskutil list. Look for your 1TB external drive—it'll show up as /dev/diskN (where N is a number like disk2). Built-in disks are usually disk0 or disk1, so double-check the size to avoid mistakes.
• Unmount the drive if it's partially mounted:

  diskutil unmountDisk /dev/diskN
  

  If that fails, force unmount with:

  diskutil unmount force /dev/diskN
  

Step 2: Wipe and Reinitialize the Drive #

Method 1: Use diskutil (Recommended—Safer & Faster Than dd) #

This command will erase all encryption data, partitions, and reformat the drive in one go:

diskutil eraseDisk JHFS+ "My External Drive" /dev/diskN

• Replace JHFS+ with ExFAT if you need cross-compatibility with Windows.
• "My External Drive" is the name you want for the drive—feel free to change it.
• Once done, the drive should mount automatically and be ready to use.

Method 2: Use dd to Fix Stubborn Cases (If diskutil Fails) #

If the encrypted partition is stuck, first wipe the first 10MB of the drive (this destroys the partition table and encryption metadata):

sudo dd if=/dev/zero of=/dev/diskN bs=1m count=10

• You'll need to enter your admin password (no characters will show as you type—this is normal).
• After this completes, run the diskutil eraseDisk command from Method 1 again, or open Disk Utility—your drive should now show as "Uninitialized", and you can follow the on-screen prompts to create a single partition.

Can I Use dd if=myImage.dd of=/dev/diskN to Write a Disk Image? #

Absolutely! Just keep these tips in mind:

• Make sure you're targeting the entire disk (/dev/diskN), not a single partition (like /dev/diskNs1—that's a common mistake).
• Ensure the drive is unmounted before running the command to avoid conflicts.
• If your image is encrypted, you'll need to decrypt it after writing to mount it properly. For regular unencrypted images, the drive should mount automatically once the write finishes.

Fixes for Failed Command-Line Erasure #

If your previous command-line attempts failed, try these troubleshooting steps:

• Check Permissions: Always use sudo for commands that modify the entire disk—without admin rights, operations will fail.
• Kill Active Processes: Use lsof /dev/diskN to see if any apps are using the drive (like Finder windows or background tools). Close those apps and try again.
• Test Hardware: Try a different USB cable or port—sometimes flaky connections cause write failures. You can also test the drive on another Mac to rule out system-specific issues.
• Unlock Encrypted Volumes First: If it's a FileVault-encrypted drive, unlock it before wiping with:

  diskutil coreStorage unlockVolume /dev/diskNsX
  

  Replace diskNsX with your encrypted volume identifier (find it via diskutil list), then enter your encryption password.

内容的提问来源于stack exchange，提问作者dezman