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CrashPlan app version 4.3 unable to connect to backup engine on OS X V10.6

Applies to:
  • CrashPlan for Small Business (Mac only)
  • CrashPlan PROe


This article describes a known issue where the CrashPlan app version 4.3 displays "Unable to connect to backup engine" when installed on Mac OS X v10.6 Snow Leopard. Existing OS X v10.6 computers that upgraded from version 4.2 of the CrashPlan app are not affected by this issue.

If you see the message "Unable to connect to backup engine" on a different operating system or version of the CrashPlan app, refer to Unable To Connect To The Backup Engine.


Version 4.3.x of the CrashPlan app when installed on Mac OS X v10.6

Recommended solution

To avoid this issue, upgrade to version 4.3 of the CrashPlan app from version 4.2.

Step 1: Uninstall version 4.3

  1. Open the Finder.
  2. Press Command-Shift-G.
    The Go to the folder dialog appears.
  3. Paste this text into the dialog box: /Library/Application Support/CrashPlan/
  4. Click Go.
  5. Double-click Uninstall.
  6. Follow the prompts to complete the uninstall process.

Step 2: Download & install version 4.2

  1. Download version 4.2 of the CrashPlan app: Home | PRO | PROe
  2. After the download completes, open the DMG installer file.
  3. Double-click Install CrashPlan.
  4. Follow the prompts to complete the installation.

Step 3: Upgrade from version 4.2 to 4.3

  1. Open the CrashPlan app.
    • CrashPlan for Home and CrashPlan for Small Business (previously CrashPlan PRO) upgrade automatically as soon as you sign in.
    • If you are a Code42 for Enterprise user, contact your CrashPlan administrator if the upgrade does not start automatically.
  2. Go to Settings > Account and view the version number to confirm the upgrade succeeded.