Troubleshooting Live Migration Issues

Applies to: Windows Server 2016


This article lists live migration issues in Windows Server 2016.

Event ID 21502

Information regarding Event ID 21502:


Event ID 20413


Live migration fails at 90~100%, and quick migration fails during virtual machine configuration online.


Nodes in cluster have different system drive letters assigned.


On the destination node, the Hyper-V VMMS event displays the following error message:

The Virtual Machine Management Service failed to register the configuration for the virtual machine "<vmID>" at "<localpath>": The system cannot find the path.

Set all nodes to use the same system driver letter on the cluster.

Event ID 20417


The Virtual Machine Management service successfully completed the live migration of virtual machine "VM" with an unexpectedly long blackout time of 63.1 seconds。


The message comes from a lower performance network when you try the live migration.


Make sure there’s enough bandwidth available for the live migration.

Try to reduce the memory during the live migration. See Virtual Machine Live Migration Overview for more information.

Event ID 21024


Both live migration and quick migration succeeds, but virtual machine loses network connectivity after migration.


Virtual machine loses network connectivity after migration even though network settings are configured correctly.


Make sure the virtual machine network settings are correct.

Check if the source and destination virtual network are in the same subnet. If the aren't, run the ipconfig /renew cmdlet to resume the network connectivity. Alternatively, assign a new IP address to the virtual machine if a static IP address is used.

Event ID 21125


Configuration setup for live migration failed on the destination node.


Make sure that name of the virtual network is the same on the source and destination nodes and try the live migration again.


Here's how to resolve this issue:

  1. Open the Hyper-V Manager console on the source and destination nodes.

  2. Select Virtual Network Manager.

  3. Verify if the virtual network names matched between source and destination nodes. Virtual switches must have the same name.

  4. Click OK to close the Virtual Network Manager window.

  5. Right-click the virtual machine on the source node and select Settings.

  6. Verify if the virtual machine is configured to use the correct virtual network.

  7. Click OK to close the Virtual Machine Settings window.

  8. Close the Hyper-V Manager console on the source and destination nodes.

  9. Open the Failover Cluster Manager console on the source node.

  10. Expand roles and then select the virtual machine.

  11. On the Actions pane, click More Actions Refresh virtual machine configuration.

  12. Perform a live migration of the virtual machine on the destination node.

Event ID 21501


Live migration of "VM" failed.

Virtual machine migration operation for "VM" failed at migration source "Host5."

Failed to perform migration on virtual machine "VM" because virtual machine migration limit "2" was reached, please wait for completion of an ongoing migration operation.


Wait to finish other live migrations or increase the number of simultaneous live migrations.


To fix this issue, open the Hyper-V Manager console, click Hyper-V Settings > Live Migrations > Simultaneous live migrations.

Note Consider host performance when changing this number.

Data collection

Here’s how to collect information before contacting Microsoft Support:

  1. Download TSS Windows CMD based universal Troubleshooting Script tool set on all nodes and unzip it in the C:\tss_tool folder.
  2. Open Command Prompt with Run as administrator and move it to the C:\tss_tool folder.
  3. Start the trace by running the cmdlet on the source and destination nodes.

    TSS rOn VML:verbose
  4. Perform the repro steps for the issue and follow instructions to stop the traces after that repro steps are completed.

    Note Collect the trace on both nodes.
  5. Download the psSDP tool to collect the logs from the source and destination nodes.
  6. Unzip the file and run the following cmdlet on both nodes:

    .\GetpsSDP.ps1 HyperV -localNodeOnly
  7. Collect all logs. zip and upload the collection on the workspace.