Last week I upgraded my 3 ESXi hosts to 5.1U1 (build 1065491), now I have about 20 VM's (out of 50 total) across all 3 hosts that have an error that the heartbeat is missing. I've upgraded VM Tools to the latest version on these VM's and ensured that tools is in fact running, even restarted the VM's.. the error will not clear. I am running Monitor version 6.50.676. Any ideas? Thanks!