cannot restore a virtual machine and a Trouble writing files, error -3956 appears when using VMware Data Recovery

Posted on 11:03 PM by Bharathvn

Cannot restore a virtual machine and a Trouble writing files, error -3956 appears when using VMware Data Recovery


Symptoms

You may experience these symptoms:
  • A restore (or a restore rehearsal) of a virtual machine fails
  • You receive the error:

    "Trouble writing files, error -3956 (Operation failed)".
    7/16/2009 16:52:14.000: 0x0a396d90: RMapGetChanges: Reporting changes to 41
    7/16/2009 16:52:14.000: 0xb42df028: $[*20750]Trouble writing files, error -3956 ( operation failed)

Resolution

Error -3956 usually indicates that Data Recovery failed to create the virtual machine during restore.

Reasons for this kind of failure:

  • The virtual machine had an incorrect device backing info at the time of backup, usually an invalid CDROM configuration.

    Workaround: Manually create a virtual machine with same the CPU, memory, etc. settings and restore just the disks to that virtual machine. This can be done by setting restore configuration to No in the restore wizard.

  • A virtual machine is on a shared storage and its datastore is accessible to multiple hosts. In this case, Data Recovery chooses an incompatible datastore during restore and fails.

    Workaround: Verify that the datastores chosen for the virtual machine by the restore wizard is visible on the ESX host that the restore is being made to. If not, choose a valid datastore manually.