vSphere HA not working after vCenter 5 Upgrade

We had a customer recently that experienced issues with HA not working after upgrading vCenter to version 5.  They were going to upgrade all the hosts to version to vSphere 5 at a later date.  This happened on 2 clusters with 4 or more hosts per cluster and 75+/- VMs per cluster.  Error is listed below.


Taken from the recent tasks pane:

vSphere HA agent for this host has an error:  vSphere HA agent cannot be correctly installed or configured    WARNING
The vSPhere HA availability state of this host has changed to initialization error.  INFO
Cannot upgrade vCneter agent.  Unknown installer error ERROR


Below are the troubleshooting step we tried.

• Disabling HA on the cluster.
• vCenter KB on SSL Certificate Checking.
• We then tried creating a new cluster and taking 2 hosts out and configuring HA and it still gave the error.

The customer contacted VMware support while we were working through this with them and so far they were still combing the logs for errors.  After 2 days or so VMware found the solution and it was very odd.

This is the resolution below.

KB 2009546 - Cannot configure HA after disabling the Host Welcome login page on an ESXi host

When we first went to this page it was blank except for the title and affected vSphere versions.  Now it is fully populated with information.

So when we were searching looking for a fix this KB wouldn't populate since it had no contents. This is now one of the errors I will ever forget.