ESXi hosts display "Registration/unregistration of third-party IO filter storage providers fails on a host" warning after power event

Products

• VMware vCenter Server

Issue/Introduction

Following a data center power outage and subsequent thermal event (AC failure), ESXi hosts may display the warning: Registration/unregistration of third-party IO filter storage providers fails on a host.

In this specific scenario, the hosts (HPE DL360) experienced an unclean shutdown due to high temperatures. While the physical hardware and services recovered after rebooting, the vCenter Server alarms remained in a "Triggered" state. Users may also see related warnings regarding "Host connection and power state" depending on the timing of the host recovery.

Environment

Product: VMware vSphere ESXi 7.x, 8.x
Hosts: HPE DL360

Cause

The warnings were triggered by the interruption of management services during an unplanned power event, where the initial registration handshake for IO filter storage providers failed during the thermal shutdown. Although these providers resume normal operation and the hosts recover physically after rebooting, the vCenter Server alarm management system often fails to clear the status automatically, resulting in "stale" alerts that persist in the UI and require manual acknowledgment to resolve.

Resolution

If the underlying storage provider connectivity is healthy but the warning remains in the vSphere Client, you can manually reset the alarm status:
1. Log in to the vSphere Client.
2. Navigate to the Hosts and Clusters view.
3. Select the impacted ESXi host.
4. Click the Monitor tab and select Issues and Alarms > Triggered Alarms.
5. Locate the alarm: Registration/unregistration of third-party IO filter storage providers fails on a host.
6. Click Reset to Green or Acknowledge to clear the warning.
7. Repeat these steps for any other hosts displaying the same warning.

[!NOTE] If a functional issue with the storage providers still exists, the alert will re-trigger within 24 hours.