6645: Acronis Managed Machine Service Crashes if There Is a USB Device with 4 KB Cluster Size Plugged In

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Last update: 20-01-2010

Update to the latest build to resolve the issue

This article applies to:

  • Acronis Backup & Recovery 10 Advanced Server
  • Acronis Backup & Recovery 10 Server for Windows (Standalone)
  • Acronis Backup & Recovery 10 Advanced Server - Small Business Server Edition
  • Acronis Backup & Recovery 10 Advanced Workstation
  • Acronis Backup & Recovery 10 Workstation (Standalone)
  • Acronis Backup & Recovery 10 Advanced Server - Virtual Edition


  1. You have Acronis Agent running on a machine;
  2. Once you plug in a USB device with a 4 KB cluster size (e.g. iPod), the Acronis Managed Machine Service crashes:

    Acronis Managed Machine Service is unavailable

  3. In the Windows Event Log (Control Panel -> Administrative Tools -> Event Viewer), there is an error entry similar to the following one:

    Source; Service Control Managed
    Event ID: 7031
    The Acronis Managed Machine Service service terminated unexpectedly.
    It has done this 1 time(s). The following corrective action will be taken in 0
    milliseconds: Restart the service.

  4. As a result of the crash you will not be able to connect to the Acronis Agent from Acronis Management Console and run the backup, restore or validation task.


Components of Acronis Backup & Recovery 10 Build 11133 or lower cannot handle the 4 KB cluster size properly.


This has been fixed and the fix is available in the latest released build of the product. See Downloading the Latest Build of Acronis Software.

To workaround the issue without downloading the latest build, unplug the USB device and reboot the machine.

More information

Most iPod models have 4 KB cluster size.