When placing a VMware host into maintenance mode, you might encounter unexpected errors that halt your progress. One of the most common and frustrating messages is “waiting for active NFC session to terminate.”
This issue doesn’t happen every time, but when it does, it can delay maintenance tasks and system updates. Don’t worry — in this guide, you’ll learn what causes this error and how to fix it quickly and safely.
Table of Contents
Understanding the Error: What Causes “Waiting for Active NFC Session to Terminate”?
Before applying a fix, it’s essential to understand the root cause.
This error usually appears when a virtual machine (VM) backup process is still running in the background. The NFC (Network File Copy) session remains active because the backup is transferring or locking VM data, preventing the host from fully entering maintenance mode.
In short:
This error means that your host is waiting for an ongoing backup task to complete.
How to Fix “Waiting for Active NFC Session to Terminate” Error
Fortunately, resolving this issue is simple and can be done in just a few minutes.
Here are two proven methods to fix it:
1. Stop Any Active VM Backup Jobs
The easiest fix is to pause or stop any running backup jobs before putting the host into maintenance mode.
Steps:
- Log in to your backup software dashboard (such as Veeam or any third-party backup solution).
- Check for active backup tasks related to the affected host.
- Stop or cancel any running backups.
- Try putting the host into maintenance mode again.
Once backups stop, the NFC session will end automatically, allowing maintenance mode to proceed.
2. Restart the VPXA Service
If the first method doesn’t work, restarting the vpxa agent on the ESXi host can help clear the stuck session.
Steps:
- Access the host via SSH or Direct Console User Interface (DCUI).
- Run the following command to restart the VPXA service:
/etc/init.d/vpxa restart- Wait for a minute, then attempt to put the host into maintenance mode again.
Restarting the VPXA service resets the communication between the host and vCenter, effectively terminating any lingering NFC sessions.
💡 Tip: Restarting VPXA does not affect running VMs — it only resets the management agent.
Preventing the Error in the Future
To avoid encountering the “waiting for active NFC session to terminate” issue again, consider these best practices:
- Schedule host maintenance outside of backup windows.
- Regularly check for stuck or failed backup sessions.
- Ensure your backup tool integrates correctly with vCenter to handle sessions cleanly.
Taking these precautions will help keep maintenance operations smooth and interruption-free.
Frequently Asked Questions (FAQs)
It means a backup or file transfer session is still running, preventing the host from entering maintenance mode.
You can fix it by stopping active backup jobs or restarting the VPXA service using the /etc/init.d/vpxa restart command.
No, restarting VPXA only resets the management agent and won’t affect running VMs.
It appears when backups overlap with maintenance tasks, causing temporary conflicts in the NFC session.
Schedule maintenance during non-backup hours and regularly monitor your backup sessions to avoid conflicts.
Conclusion
This error in VMware is common but easy to fix. It usually happens because of an active backup session or a stuck NFC connection.
To resolve it, either stop the running backup or restart the VPXA service using /etc/init.d/vpxa restart. Both methods work effectively and can get your host into maintenance mode within minutes.
Stay proactive by managing your backup schedules, and you’ll avoid this issue in the future.
