If you're like me in that you create VMware ESX demo environments within VMware Workstation, you may have recently discovered that the upgrade to v3.5 has some odd quirks. Specifically, with many processor classes, although you can build the environment you are no longer able to boot any virtual machines. The ESX server simply halts when you attempt to click the green VCR button to start the VM.

Well, I did a little digging into this problem recently and discovered that there are some upgrades to 3.5 that improve its performance but eliminate our VM-in-a-VM friend. I wrote about it in this week's MCPmag.com quickTIP:

According from a document from xtravirt.com, this new hardware-assisted virtualization support may enhance virtualization, but it also comes at a price. The document reads, "ESX 3.5 enables support of new Hardware Assisted Virtualization [a function which requires chipset support] which may not exist in the majority of chips currently in circulation."

The document goes on to mention that AMD Quad Core "Greyhound" chipsets have been successfully tested to work with VM-in-a-VM. But these chipsets are relatively new, and so it's likely you don't have them in your current environment.

Are you having the same troubles? If so, let us know. Specifically, the processor type and class you're using that either works or does not work.