vSphere HA "Failover Operation in Progress" Stuck Alarm

03 February 2025

Fix: turn vSphere HA off and on again.

vCenter > Cluster > Configure > vSphere Availability > vSphere HA is Turned ON > Edit: disable it, save, then edit again and enable it.

Notes:

Running VMs are not affected, but there is no HA protection while it's off.
Pending tasks (for example scheduled snapshots) must finish first, vCenter won't let you change it until then.
If one host still shows the error, right-click it > Reconfigure for vSphere HA.

More info.