Probelmatic Host in vCenter

I'm having an issue with one of my ESXi 5.1 Hosts in vCenter (we are running the VCSA version 5.1.0.5200 Build 880472).

The Host can be managed directly without any issue. When connecting via vCenter though, the Host shows as disconnected.

If I try to Connect the Host then it gets to 90% and vSphere client crashes.

If I try to Remove the Host from vCenter it gets to 90% and vSphere client crashes.

I'm not sure if there are some logs somewhere that may help pinpoint the issue?

Has anyone else seen this kind of behaviour?

Thanks,