I'm running ESXi 6.5 as a VM under Workstation 12, which in turn is running under Windows Server 2012 R2 Essentials. I am unable to create VMs under ESXi 6.5.
From the Navigator I click on Host. From the Host configuration panel, I click on Actions and select Create/Register VM. Then I select Create a new virtual machine and click on Next. In the name field, I enter a name (Windows 10 Pro x64 Test). For Compatability, I leave the setting at ESXi 6.5 virtual machine. For Guest OS family, I select Windows, for Guest OS version, I select Microsoft Windows 10 (64-bit). Then I click Next. I have only one datastore, so that is displayed and automatically selected. It has a capacity of 292.5GB, 291.55GB free, the type is VMFS5, Thin provisioning is set to Supported and Access is set to Single. I click Next taking me to the Customize settings panel. I leave all the Virtual Hardware settings at their defaults, except for Video Card which I change from Specify custom settings to Auto-detect settings. I don't enter/change any VM Options. Click Next. This takes me to the Ready to complete panel. I click Finish.
Then I get a VM config error message: The VM configuration was rejected. Please see browser Console. The browser console states "Failed - The operation is not allowed in the current state."
When I Google this, I find a few YouTube videos with titles like "Installing Windows 10 under ESXi," but when I watch these videos, they are all running ESXi under vSphere, not under Workstation 12, and the browser interface looks completely different from what I see on my machine. Also, what does "current state" refer to? The instance of ESXi? The instance of the VM I'm trying to create? The datastore? What state is whatever-the-error-message-is-referring-to in and what state should it be in? I wish it would give more complete messages, like the X is in state Y and it needs to be in state Z.