VM reconfiguration and vmotion fails with error "A general system error occurred: Undeclared fault Cause: An error occurred during host configuration: Failed to attach all ports."

Products

• VMware NSX

Issue/Introduction

• When attempting to power on new Virtual Machines (VMs) or relocate existing VMs in a VMware NSX-T environment,  the operation fails.
  
  
• When  vMotion is attempted it fails with error "A general system error occurred: Undeclared fault Cause: An error occurred during host configuration: Failed to attach all ports."
  
  
• When trying to reconfigure a virtual machine it fails with error "An error occurred during host configuration: Failed to attach VIF: bad0006.Failed to attach virtual network interface Unknown to logical switch 5bxxxxxx-9xx1-4xx1-8xxx-6xxxxxxxxxxf, message from NSX: bad0006"

• When attempting to reconfigure/migrate VMs you may also observe error "Failed to add DVPort in vmkernel: status(bad=006) Limit exceeded while powering on the VM /relocation to this ESXi host after the reconfiguration."
  
  
• Log lines similar to the below are encountered in /var/log/vpxa.log on the affected ESXi host:

2025-09-22T19:34:34.037Z info vpxa[17607500] [Originator@6876 sub=Default opID=432f752f-01-29] [VpxLRO] -- ERROR task-206115 -- vpxa -- vpxapi.VpxaService.registerVm: vim.fault.PlatformConfigFault: --> Result: --> (vim.fault.PlatformConfigFault) { --> faultCause = (vmodl.MethodFault) null, --> faultMessage = (vmodl.LocalizableMessage) [ --> (vmodl.LocalizableMessage) { --> key = "com.vmware.esx.hostctl.default", --> arg = (vmodl.KeyAnyValue) [ --> (vmodl.KeyAnyValue) { --> key = "reason", --> value = "Failed to add DV Port in vmkernel: Status (bad0006)= Limit exceeded" --> } --> ], --> message = "Operation failed, diagnostics report: Failed to add DV Port in vmkernel: Status (bad0006)= Limit exceeded" --> } --> ], --> text = "" --> msg = "An error occurred during host configuration." --> }

• Log lines in /var/log/nsxaVim.log or nsx-opsagent logs on the ESXi host might indicate errors during the resync.py script execution, such as:

2025-10-06T21:17:49Z In(14) nsxaVim: [44225008]: INFO [resync] resync.py: caught exception: {'fault': 'too many values to unpack (expected 2)'}^@

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Environment

• VMware NSX

Cause

• This issue occurs due to an accumulation of stale NSX-backed Distributed Virtual Switch (DVS) ports on ESXi hosts. 
  
  
• When VMs are frequently created and deleted, NSX-T is expected to clear associated logical ports. However, the resync.py script, which is responsible for the periodic cleanup of these stale dvPorts, fails to execute correctly.

Resolution

• This issue is resolved in VMware NSX 4.2.x and later , available at Broadcom downloads. 
• If you are having difficulty finding and downloading software, please review the Download Broadcom products and software KB.
  
  
• If an immediate upgrade is not feasible, a workaround is available for affected ESXi hosts in earlier NSX-T versions.
  
  
• Workaround:
  
  If you are unable to upgrade to NSX-T 4.2.x or later, you can apply the following temporary workaround on the affected ESXi hosts to clean up stale ports. 

Perform these steps on each affected ESXi host:

1.  Put the ESX host in maintenance mode.
   
   
2. SSH to the ESX and download the modified resync.py script attached to this KB and move to /tmp/ directory on the host.
   
   
3.  Backup existing resync.py.
   

   cp /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync.py /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync_bk.py

4.  Disable VisorFSPristineTardisk.
   

   vsish -e set /config/VisorFS/intOpts/VisorFSPristineTardisk 0

5. Replace existing resync.py with modified resync.py and change permission.
   
   

   cp /tmp/resync.py /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync.py
   
   chmod 444 /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync.py
   
   chown root:root /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync.py

6.  Execute the resync.py script
   
   

   python /usr/lib64/vmware/nsx-opsagent/pyvim/nsxa/resync.py 3600 0 2>&1

7. The resync logs are present in the /var/log/nsxaVim.log file
   
   
8. verifying that stale ports are cleaned up.
   
   
9.  Enable VisorFSPristineTardisk.
   
   

   vsish -e set /config/VisorFS/intOpts/VisorFSPristineTardisk 1

10.  Exit maintenance mode
    
    This workaround should be applied to all ESXi hosts in the cluster that are experiencing or are susceptible to this issue.