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Investigating network devices and device settings as a cause of VMware Converter failures (1004615)


This article provides steps to verify if the configuration of network interface cards (NICs), switches and switch ports, firewalls, and load-balancer devices are causing issues when using VMware Converter's cloning process.


During the cloning phase of conversion, data is being transferred from the source computer or virtual machine to the destination. A break in the transfer of data caused by network errors or improper network configuration causes failures or very slow conversion performance.

Determine if network device settings are interfering with the conversion or cloning process

To determine if network device settings are interfering:
  1. Verify that there are no host network interface cards (NICs) or network devices in the VMware Converter environment that have been statically configured to be at a different speed or duplex. This includes settings on the source operating system, switches and networking devices between the source and destination and the destination server.

    If the destination in an ESX/ESXi server, verify the speed and duplex setting using the Virtual Infrastructure client: click Configuration > Network. Observe the settings for the VMKernel virtual switch. For more information, see Configuring the speed and duplex of an ESXi/ESX host network adapter (1004089)
  2. Ensure you check the physical speed indicator lights on the NICs and switches and verify that each end has a corresponding speed and duplex. In general ensure all devices are using auto negotiation. Check this setting in the operating system or drivers, and then verify the operation on the indicator light on the device. If you must use manual or static settings, ensure that the setting is not higher than both the device itself and the device it is connected to (peer) is capable of operating.

    Note: In some cases, auto-negotiation may fail. In this case, use static configuration on both sides of that network segment. Ensure you set corresponding duplex and speed settings between the source and its peer to avoid a duplex mismatch condition. For more information, see Duplex Mismatch (

Determine if the failure is being caused is a problematic NIC, network device, or cable

The easiest approach is by simplifying the networking environment (elimination). Gradually reducing the number of network devices and network segments involved in the conversion, verify speed indicators, and swap for known good equipment and cables.
To determine the cause of the failure is a NIC, network device, or cable:

  1. If applicable, convert directly to the ESXi/ESX host rather than via vCenter Server. If converting to a standalone virtual machine file over a network share, try performing the conversion to a locally attached drive that is not included in the source of the conversion.

  2. Bypass or disable any network load-balancers between the two end-points.

  3. If you are using a security firewall or stateful packet inspecting (SPI) firewall, ensure the connection is not being blocked as malicious traffic. You may need to review the alerts or logs to determine this.

  4. Try connecting the source and/or destination servers to a different port on the switch. Some switches may have failing or faulty ports while other ports work properly.

  5. If you use a managed switch, check the administration console for logged connection errors or corrupt packets.

  6. Use a dedicated switch rather than a shared network switch between the source and destination.

  7. Swap the network cables between the switches or servers with known good cables.

  8. Use a crossover cable between the source and destination. When using this configuration ensure the speed and duplex indicators on the physical hardware correspond between the two systems.

  9. Bypass network conversion. Create a standalone virtual machine on the source operating system's file system, and then copy or convert it manually to the destination.

    Note: If you are using an ESXi/ESX server as the destination, you must use vmkfstools -i to import the virtual machine.

Additional Information

For more information related to troubleshooting cloning problems, see Troubleshooting issues when vCenter Converter fails during conversion (1006292) .


converting-vm converting-vm-fails vcenter-converter

See Also

Update History

08/15/2012 - Updated for 4.x and 5.x versions. 06/21/2013 - Added 5.1 to product versions list.

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