I'm using TrendMicro DSM 9.0 as the antivirus solution for our VDI pilot. We just upgraded the VMware infrastructure from ESX 5.0 to 5.1 U1, along w/ View, vShield Manager, vCenter.
For almost every VM I've upgraded the VMware tools on, I see their status in the DSM Manager as "Anti-Malware Engine Offline" sometimes, and other times most of them switch back to "Online". For the VM's that have not been upgraded yet, they stay consistently as "Online".
I've verified the View Agent has been upgraded properly. I've verified the vShield system driver is running on the VM's. I'm not sure where to go from here.
Let me know what other details I can provide!