Who is affected:
Customers who are using VMware vSphere ESX 4.0 and are wanting to install update 1, via VMware Update Manager (VUM).
Upgrading ESX 4.0 to 4.0 U1 using VUM fails or times out. Rebooting host results in a PSOD and the host has to be re-installed.
Please disable any 3rd party hardware monitoring agents running on the ESX 4.0.0 server before applying the update.
Customers that have already run into this issue and have installed the update but have not rebooted, need to contact Support.
The 3rd party agents can be enabled again after the upgrade is completed.
ESX 4.0 U1 is no longer available for download.