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CrashPlan Support

External Drive Stops Backing Up On OS X

Applies to:
  • CrashPlan for Home
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This article is intended for CrashPlan for Home users. For Code42 CrashPlan and CrashPlan for Small Business documentation, read this page on our enterprise support site.


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 However, CrashPlan is looking for the folder with the original name, which is no longer valid.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