I know many of you have been asking about ESXi support for the latest Mac Pro 6,1 that was released from Apple late last year and I just wanted to give a quick update. VMware Engineering has been hard at work on getting this new platform certified and supported with ESXi, however, there were some unforeseen challenges that is currently preventing the current version of ESXi to run on the new Mac Pro.
VMware is working closely with Apple's hardware team to resolve these issues and we expect to have a Mac Pro 6,1 supported with ESXi 5.5 in the future. In the meantime, if you wish to evaluate ESXi on the new Mac Pro (though not officially supported), you can sign up for the new vSphere Beta and run a Beta version of ESXi on the new Mac Pro.
Here is a screenshot of Mac Pro 6,1 running the Beta version of ESXi:
There are a couple of workarounds that is required for right now, which will all be resolved by GA. For more details, please refer to this VMTN thread.