VMX unrestricted guest errors with Workstation 14 or Fusion 10

With the new Workstation 14 and Fusion 10 there is also a new requirement for your CPU’s. This unfortunately has not been clearly communicated about by VMware. When you try to start a VM and get the error:

This host does not support virtualizing real mode. The intel “VMX unrestricted Guest” feature is necessary to run this virtual machine on an Intel processor.

Module ‘CPUIDEarly’ power on failed

Failed to start the virtual machine

You’re one of those lucky ones with a CPU that is too old.

So for example the iMac “Core i7” 2.93 27-Inch (Mid-2010) which has a Quad Core 2.93 GHz Intel “Core i7” I7-870 (Lynnfield) processor and belongs to the Intel Nehalem family does not have the required CPU feature: VMX unrestricted guest.

This excellent post from VMTN user Bluefirestorm shines a light on it:

Re: What is VMX Unrestricted Guest?

The documentation has an update on what processors it supports (but you’re a real star if you find that before buying the upgrade)

Processor Requirements for Host Systems (Workstation)


System Requirements for Fusion

If you have an older processor then you actually can get VMs to run using a vmx hack, but it has been reported to be unusable slow.

monitor.allowLegacyCPU = “true”

from a post from Ulli here: ESXi 6 VM unusable slow in WS 13 beta

To quote Ulli freely, “booting a ESXi 6 vSphere VM in Workstation 12.01 went from 30 seconds  to 12 hours in Workstation 14 beta”.

That really falls into the category unusable if you ask me.

So my advice is to test before you buy!

You can use a 30 day time limited trial to see if it works out for you.

If it works out for you then buy and assign the license to the install and the time limit will be removed (so no need to reinstall)

Try VMware Fusion or Fusion Pro.

and for Workstation 14 the link is:

Try VMware Workstation

Look for the “Download Now” link at the top right of your screen.

Update 2017/10/07: As a challenge last week I decided to see if I could build a little tool that can detect if your CPU has unrestricted guest capabilities. I succeeded on that, it requires you to boot your host from a custom CD (yes those physical things) For more details and the iso image, please see this post at vmtn: https://communities.vmware.com/message/2709089#2709089 If I decide to spent more time on that and make it nicer I will upload the iso down there.

Author: Wil van Antwerpen

Wil van Antwerpen is a software developer who loves to work on Open Source and dabble a bit with VMware products. He likes to help people out as that is a good way to learn more. He is the author of Vimalin Backup (https://vimalin.com) which is virtual machine backup software for VMware Fusion and VMware Workstation Pro.

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