Hardware status tab is blank when upgrading from vCenter Server 4.0 to 4.1
When upgrading vCenter Server from 4.0, 4.0 U1 or 4.0 U2 to vCenter Server 4.1 in a linked-mode environment the Hardware Status tab will be blank on vCenter Servers not yet updated to 4.1.
The Hardware Status tab is functional for any vCenter Servers that are upgraded to 4.1 in your environment,
The Hardware Status tab is blank (without any error messages) on your non-upgraded vCenter Servers.
This issue occurs due to incompatibilities with the vSphere Client between 4.0 and 4.1.
vCenter Server 4.1 can exist in Linked Mode with other instances of vCenter Server 4.1 or vCenter Server 4.0 and later. If the vSphere Client that corresponds to the version of vCenter that you are trying to connect is not installed on your system, you are prompted to download and install that version of the vSphere Client. After both versions of the client are installed, you can access vCenter Server linked objects with either client.
For linked mode environments with vCenter Server 4.0 and vCenter Server 4.1 you must have vSphere Client 4.0 Update 1 and vSphere client 4.1 (the vSphere Client 4.0 will not work in this case). You must either remove the older vCenter Servers from linked-mode and manage them on their own, or upgrade them to vCenter Server 4.1.
All hosts managed by vCenter Servers with versions less than 4.1 will display no data under the Hardware Status tab if you have not installed all correct versions of the client and are connecting through your vCenter Server 4.1 server.
To resolve this issue:
Remove your vCenter Server 4.0 servers from linked mode: Click Start > VMware > vCenter Server Linked Mode Configuration > Uninstall
Upgrade to 4.0U1, 4.0U2 or 4.1. For more information, see: Upgrading to ESX 4.0 and vCenter 4.0 best practices (1009039) Upgrading to ESX 4.1 and vCenter Server 4.1 best practices (1022104)
Install the vSphere Client. For more information, see vSphere Upgrade Guide.