- You have Acronis Virtual Appliance.
- Backup of a VM fails at the disk attach stage (hot-add backup mode when backed up disks are attached to the appliance) with the following error:
Error code: 64
Fields: $module : esx_srv_glx_pic_43759
Message: Awaiting task 'AttachScsiHardDisk' has failed.
Error code: 202
Fields: fault : MethodFault, $module : esx_srv_glx_pic_43759
Message: Cannot complete the operation because the file or folder disk_01_10.vmdk already exists
Disk names of the backed up VM differ only by "-", "_" or a space. For example, the VM contains disks named disk_01_10.vmdk and disk-01-10.vmdk. These signs and blank spaces are replaced by the underscore sign when vCenter attaches links to these disks to the virtual appliance. The real VM virtual disks are not attached for safety purposes. Instead links to the disks are used to prevent any damage to the production VM in case of accidental or mistaken deletion or changes in configuration of the appliance. Due to this replacement the links become identical: disk_01_10.vmdk. Therefore, only one of these disks can be attached to the Virtual Appliance and attempt to attach the 2nd disk fails causing the entire backup operation failure.
On the affected VM, rename one of the disks.
Alternatively, back up the VM using Acronis Backup Windows Agent for VMware instead of Virtual Appliance so that backup is not performed in hot-add mode and thus disk attach is not required.