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Unrecoverable ERROR using Insider Edition of Windows 10.

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Hello all,

So I had an update with windows 10 Insider Edition and I think this is what started causing my issues. I am unable to boot into any of my windows 10 VMs using VMware Workstation Pro 16. I attached the vmware.log file and Here is the Error I am getting:

VMware Workstation unrecoverable error: (vcpu-1)

VERIFY D:\build\ob\bora-16894299\bora\vmcore\monitor\ulm\platform\windows\ulm.c:967

A log file is available in "C:\Users\Owner\Desktop\Windows 10RECOVERY\vmware.log". 

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Any help on steps I can take from here would be greatly appreciated.

NOTE: I needed to use insider edition of windows on my host machine for a different project which needed to be done for Nvidia passthrough to WSL but I dont really need that anymore. I just havent found a way to downgrade back to regular version of windows without a fresh install. Im new to the VM world so I am just trying to figure this out as I go.

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Virtuoso
Virtuoso

The crash looks like is on the User Level Monitor (ULM). The ULM is a ring 3 hypervisor that VMware Workstation/Player uses when it detects Hyper-V/VBS/DG. When the Hyper-V on the host is disabled, the ring 0 VMM will be used.

2020-10-27T01:38:34.423-07:00| vmx| I005: Monitor Mode: ULM

You can try removing Hyper-V from the host. Use this KB as reference

https://kb.vmware.com/s/article/2146361

You should no longer get the suggestion to disable the side channel mitigations if the ring 0 VMM is used. In the vmware.log, the Monitor Mode should show CPL0 instead of ULM.

2020-10-27T01:38:34.423-07:00| vmx| I005+ You are running this virtual machine with side channel mitigations enabled. Side channel mitigations provide enhanced security but also lower performance.

2020-10-27T01:38:34.423-07:00| vmx| I005+

2020-10-27T01:38:34.423-07:00| vmx| I005+ To disable mitigations, change the side channel mitigations setting in the advanced panel of the virtual machine settings. Refer to VMware KB article 79832 at https://kb.vmware.com/s/article/79832 for more details.

I don't know what other problems might arise as the host is an insider preview version of Windows 10.

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Virtuoso
Virtuoso

The crash looks like is on the User Level Monitor (ULM). The ULM is a ring 3 hypervisor that VMware Workstation/Player uses when it detects Hyper-V/VBS/DG. When the Hyper-V on the host is disabled, the ring 0 VMM will be used.

2020-10-27T01:38:34.423-07:00| vmx| I005: Monitor Mode: ULM

You can try removing Hyper-V from the host. Use this KB as reference

https://kb.vmware.com/s/article/2146361

You should no longer get the suggestion to disable the side channel mitigations if the ring 0 VMM is used. In the vmware.log, the Monitor Mode should show CPL0 instead of ULM.

2020-10-27T01:38:34.423-07:00| vmx| I005+ You are running this virtual machine with side channel mitigations enabled. Side channel mitigations provide enhanced security but also lower performance.

2020-10-27T01:38:34.423-07:00| vmx| I005+

2020-10-27T01:38:34.423-07:00| vmx| I005+ To disable mitigations, change the side channel mitigations setting in the advanced panel of the virtual machine settings. Refer to VMware KB article 79832 at https://kb.vmware.com/s/article/79832 for more details.

I don't know what other problems might arise as the host is an insider preview version of Windows 10.

View solution in original post

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Contributor
Contributor

That was quick and painless I thought I was doomed. The first link resolved my problems. I didnt have Hyper-V installed or enabled and only the group policy changes at the end of the instructions was the only change I had to make. Changing from "Not configured" to "disabled" and a restart of the host machine did allow me to get into my VM. Thanks so much for your help!

I know there are some issues when you have docker running on the host system but would there be a way to have docker and VMware coexist? Ive tried familiarizing myself with the VIC containers but I havent actually been able to figure out how to fully operate them easily compared to having docker installed.

Just a side note: I have a seperate server running a free license of ESXi 7and I use my Workstation to connect to that as well. Which was where I attempted to run the VIC containers. I've gotten it to work once but only when I had the trial version of ESXi 6.7.

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Virtuoso
Virtuoso

The raison d’être of ULM is to allow VMware Workstation Pro/Player VMs to run even if Hyper-V is enabled. Prior to versions 15.5.5/16, VMs will not power up when Hyper-V is enabled on the Windows host.

https://blogs.vmware.com/workstation/2020/05/vmware-workstation-now-supports-hyper-v-mode.html

https://docs.microsoft.com/en-us/troubleshoot/windows-client/application-management/virtualization-a...

So if you install Docker on Windows, that will require Hyper-V to be enabled again; and it's back to the problem of ULM crashing in an Insider Preview Windows 10 host. So you might have to go back to a Windows 10 2004 host if you want to enable Hyper-V and let VMware use ULM for VMware and Hyper-V to co-exist.

Alternatively, you could also try using nested virtualisation (running a VM in another VM or enabling Hyper-V inside a VM). In the VM Processor setting, there is a checkbox "Virtualize Intel VT-x/EPT or AMD-V/RVI" that has to be enabled to allow nested virtualisation. This checkbox is the VM equivalent of enable Intel VT-x in UEFI/BIOS of a physical machine.

For nested virtualisation, it will be better to have a Haswell or newer CPU as it has features such as nested paging accessed/dirty bit, VMCS shadowing make for running nested VMs more efficiently. The VMCS shadowing feature is not available on all Haswell and newer CPUs but it seems to be indicated by vPro Eligibility "Yes" in the Intel ARK specification page (and some expensive CPUs don't have it, go figure).

You should be able to connect to an ESXi server from Workstation Pro; I don't think free license version of ESXi would be an issue. ESXi can also support nested VMs.

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