Issue with Update 1 and COS Agents

I wrote this article after the KB was release but forgot to click “publish”. Those planning to upgrade their vSphere environment to Update 1 please read the following:

KB Article 1016070

Issue
Upgrading ESX 4.0 to 4.0 U1 fails or times out and rebooting the host results in a purple diagnostic screen

Who is affected
Customers using VMware vSphere 4 upgrading to Update 1 with 3rd party management agents running.

To identify whether you have a 3rd party management agent installed:

1. Log into the ESX host as root.
2. Run the esxupdate query command.
3. Anything listed under New packages: may be a 3rd party management agent in the service console.

Note: Consult your hardware vendor documentation for specific package names that are installed in the service console.

Solution

To avoid this issue, prior to the update, disable all 3rd party management agents running on the ESX 4.0.0 server before applying the update.

Note: The 3rd party management agents can be enabled after the upgrade is completed.

If you have already updated the ESX host, do not reboot the ESX host. Open a support request with VMware support. For more information, see How to Submit a Support Request.
WARNING: Rebooting the host means the host has to be reinstalled because it is not recoverable after a reboot.

WARNING: If you have virtual machines running on local storage, they may not be retained if you reinstall ESX 4.0 as a result of this issue. Contact VMware Support for assistance in recovering those virtual machines.