Template shows as Disconnected in vCenter Server

[TIVA]

My environment is ESX 3.5 Update 5 and VI 2.5.

I permanently find all templates on several ESX hosts displayed as disconnected.

I tried three ways suggested in discussions and in VMWare KB:

service vmware-vpxa restart

service mgmt-vmware restart

VirtualCenter Server service restart

These services restart helps but only for a couple of hours and templates get disconnected again.

I can't restart ESX servers because they hosts important production VMs.

Is there any way to fix root cause of this issue and prevent disconnections in future?

Waiting for any suggestions...

[msatya]

might be virus iiinfected or please install some new hot fix

-------------------------
please award points if you see fit.Thanks

[TIVA]

I've tried to update vCenter Server from U2 to U6 and that did the trick. My templaes stay connected for several days which never occured before.

There was a fix in U5 which affected session between vCenter and ESX timeout and I guess helped with templates.