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jsalton1
Contributor
Contributor

VMware Workstation 15.5 unrecoverable error (vcpu-0) Exception 0xc0000005 (access violation)

Hi,

I get this error on all my VMs after having installed Workstation on a new Windows 11 machine. This includes new VMs created on the Win 11 host. I tried reducing the number of CPUs/cores to 1/1 but the performance is terrible and unuseable.

Does anyone have a proper fix where I can get the performance back and allocate more than one core to a VM please?

Thanks,

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wila
Immortal
Immortal

Hi,

Check the vmware log file and search for a line that has "monitor mode" in it.

There's either:

monitor mode ULM

or

monitor mode CPL0

If your log file has the line:

monitor mode ULM

then that means that you are running in User Level Mode and thus Workstation cannot use VMware's hypervisor, but instead it has to go through the Hypervisor API that Microsoft provides.

Only when Monitor mode returns CPL0 it is running in ring 0, a.k.a. no hypervisor.

Monitor mode CPL0 (Current Privilege Level 0) is required for VMware Workstation to be able to use their own hypervisor.

See also:

https://communities.vmware.com/t5/VMware-Workstation-Pro/MikroTik-RouterOS-boot-speed-is-drastically...

In order to turn off ULM/Hyper-V mode, run the following command at the host in windows command-line with Administrator privileges:

bcdedit /set hypervisorlaunchtype off

Reboot the system to activate your changes.

If you want to go back to Hyper-V mode again, then you can enable it like this:

bcdedit /set hypervisorlaunchtype auto


See also:

Note that you also might have to disable Memory Integrity.

Windows Security -> Device Security -> Core Isolation details

Don't forget to reboot the host after making any of these changes.

Best of luck,

--
Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
shift7
Contributor
Contributor

I received this error when I copied a Win10 guest (suspended)
from: Workstation 15. on Win8.1 Pro
to: Workstation 16.0 on Win11 Home

These suggested solutions did not make any difference:
bcdedit /set hypervisorlaunchtype off
Windows Security -> Device Security -> Core Isolation details

Upgrading to Workstation 17.5 fixed it. (so far)
Thanks

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