Console Mouse Not Working in Windows 2012 VMs

I recently ran into some problems while deploying a Windows Server 2012 R2 VM in my vSphere 6.5 U2 lab. I’ve come to expect that the console mouse response is going to be terrible until VMware Tools is installed, but for some odd reason I had no mouse control whatsoever. Thinking it may be a quirk of the Web Console, I tried both the Remote Console and the HTML5 client to no avail.
The VM appeared to be healthy and would register keyboard input, but the motion of the mouse cursor was erratic or the cursor would not move at all. Thinking that I just needed to battle on and get Tools installed, I attempted to use the keyboard for this purpose – what a chore. You think it would have been easy, but the installer kept losing focus and falling behind other open windows. Many of the windows keyboard shortcuts I’d normally use were not functioning because they register on my laptop – not in the console. I couldn’t RDP to the VM either because the NIC needed to be configured with a valid IP address.
After doing a bit of research, it appeared that display scaling could cause all sorts of mouse issues – but this didn’t appear to be applicable in my case. That’s when I stumbled upon a communities thread that mentioned adding a USB controller to the VM. Even though my VM was ‘Hardware Version 13’, the USB 2.0 controller isn’t added by default.
I managed to get to the device manager using the keyboard, and you can see that the virtual hardware will use a PS/2 a mouse in the absence of a USB controller:

I then went ahead and added the basic USB 2.0 controller to the VM and booted it up.

 usual laggy – but working – mouse functionality had returned. You can see that the presence of the USB controller triggers the addition of a USB HID-compliant mouse device. In fact, there are two there in addition to the PS/2 mouse – not sure why.

 

At any rate, this seemed to fix the problem. I can only assume that newer builds of Windows don’t like the PS/2 mouse support offered by vSphere. In all fairness, the PS/2 standard is ancient and akin to using a serial mouse a decade ago. We’ve already seen the need for SATA controllers due to the dropping of IDE CD support in modern guest operating systems. I suspect that PS/2 mouse and keyboard support will be going the same way at some point.