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This article applies to Code42 for Enterprise version 4.

Code42 Support

External drive stops backing up on OS X

This article applies to Code42 for Enterprise version 4.


If an external drive that is backing up or serving as a backup destination stops working, you may experience one or more of the following symptoms:

  • CrashPlan may report that the backup is 100% complete, even though the external drive isn't backing up
  • The external drive's name is appended with a "1" (e.g., USB Disk renamed USB Disk 1)
  • The external drive is duplicated in your backup file selection
  • If the drive is used as a backup destination, CrashPlan reports "Backup location is not accessible"


CrashPlan app on Mac OS X backing up an external drive, or backing up to an external drive


This issue is typically caused by a drive that didn't cleanly unmount (e.g., due to a power outage, disconnected without ejecting, etc.). When this happens, the drive can leave behind a "ghost" folder in /Volumes, even though the drive is no longer mounted. When the drive re-mounts, your Mac sees that the folder name for the drive is taken, so it appends a “1” to the drive name. However, CrashPlan is looking for the folder with the original name, which is no longer valid.

To determine if you have a duplicate drive:

  1. Open Applications > Utilities > Terminal
  2. Enter the command: cd /Volumes/
  3. Press Enter
  4. Enter the command: ls
  5. Press Enter

Do you see the external drive name? Do you see one ending with a “1”? If so, this duplicate drive is causing the issue.

Recommended solution

  1. Stop the CrashPlan service
  2. Make sure your volume is disconnected
  3. In the Finder, go to /Volumes
  4. Delete the drive that is appended with 1
  5. Reconnect your volume (it should appear in /Volumes/ without the 1 ending)
    You can check this using Terminal or the Finder
  6. Start the CrashPlan service