I've noticed a few intermittent issues over the past few months with our Zenworks imaging server, that seem to be increasing, that seem to revolve around zenworktodo not communicating properly with the Zenworks server (11.3.1, Server 2008 R2, hosted on VMWare vSphere 5.5).

Issue 1 - Zenworks is unable to download imagex.exe from the server (TFTP error)
Issue 2 - Zenworks does not recreate the boot loader files on the OS disk, resulting in an unbootable OS
Issue 3 - Zenworks is not setting the imaging flag to true, resulting in a lab full of identically named PCs and GUIDs after imaging.

I recall reading somewhere about issues with TFTP on VMWare hosted virtual machines - I was wondering if anyone else has come across similar issues? It is the intermittent nature of these that makes it harder to troubleshoot.