since the latest W11 updates my W10 vm's are extremely slow...

[DrWhoIs]

does anyone has any idea why my W10 x64 vm's are so slow after installing the W11 22H2 update?

i also had to 'disable side channel mitigations' before i could boot my vm's again...

[wila]

Hi,

Most like it is because you're running your VMs under the Windows hypervisor API instead of the old VMware hypervisor.
Not because you selected that, but because Microsoft has enabled it without asking and because of that VMware Workstation has to switch to MS's hypervisor in order to be able to even run.

--
Wil

[DrWhoIs]

Hi Wil, 

cheched to see if hyperv was running but it isn't...

monitor mode is ULM... so i guess that is ok...

[DrWhoIs]

also, making a snapshot is completely hogging my system, to the fact that i can barely use the mouse...

although there isn't much disk usage....

making a snap of a simple w10 vm with 16gb mem takes now 15 minutes and in that time the whole vm is totally unresponsive

totally no idea what is going on, i only see that vmx service and system (ntoskernel) taking a lot of cpu (and no disk activity)

[wila]

Hi,

---

@DrWhoIs wrote:

Hi Wil, 

cheched to see if hyperv was running but it isn't...

monitor mode is ULM... so i guess that is ok...

---

LOL, nope, that means exactly what I said.. you're running under MS Hypervisor API's.

Slow snapshots is another sign of that.

There can be reasons to keep it like that (see the KB article below), but it is also known for causing issues.

monitor mode ULM

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:

• Workstation 16 Pro Error "Virtualized Intel VT-x/EPT is not supported on this platform
• https://kb.vmware.com/s/article/2146361

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.

Good luck!

--
Wil

[DrWhoIs]

hi Will,

i already disabled the hypervisorlaunch prior to this posting, as well as the core isolation...

didn't change things...

did shutdown of the vm en rebooted, still monitor mode is ULM?

so the question is how to get rid of it...

[DrWhoIs]

so disabled the only Hyperv related service also: hv hostservice

doesn't change a thing

what baffles me is that according to windows features dialog hyperv isn't even installed....

so i guess i'll use the command line to uninstall hyperv

and then the question will be what i'll break doing that...

[DrWhoIs]

it seems i can't get rid of hyper v at all...

[DrWhoIs]

looks like this has to be disabled as well?

Manage Windows Defender Credential Guard (Windows) - Windows security | Microsoft Learn

anyone done this?

they enabled Virtualization-Based Security by default in w11 22h2...

i guess that is still firing hyperv?

[wila]

I think so.
Microsoft is making it very hard to disable this part. It's not transparent at all.

--
Wil

[DrWhoIs]

i'm scared as hell to follow those instructions...

do you have the 22H2 tech preview installed?

[wila]

Hi,

---

@DrWhoIs wrote:

do you have the 22H2 tech preview installed?

---

Not on Windows 11, no.

--
Wil

[DrWhoIs]

Windows 10 or Windows 11 may BSOD in a VM on VMware Workstation while using Host VBS Mode (90134)

[wila]

From what I've read VMware Workstation is expected to arrive this week (I guess tomorrow?)

Your KB article says it is fixed in there.

--
Wil

[DrWhoIs]

at least there is a v17 announcement to be found in google cache dated 5 days ago

so i guess they pulled the version 

if i would be sure of a release by tomorrow i wouldn't bother disabling VBS (which is not that straightforward)...

[DrWhoIs]

i've tried every way that i can find to disable hyperv / VBS / credential guard using 

Manage Windows Defender Credential Guard (Windows) - Windows security | Microsoft Learn

it simply does not work

it's not active by group policy, the registry entries do not exist, the bcdedit command fails....

so there is afaics no way to disable it, and my vm's keep running in ULM mode which makes them unreliable and not workable...

please Vmware, release v17 asap...

[DrWhoIs]

workstation 17 released today

AND I CONFIRM THAT ALL PROBLEMS ARE GONE

CPL0 mode again!

[wila]

Woohoo!

[biowizard]

Hi Folks,

I've also been suffering from a massive slowdown of some of my VMs since upgrading Win 10 Pro to Win 11 Pro.

One setting I've found in Windows 11 which DOES seem to restore my former speed, is to turn off "Memory Integrity" in the "Core Isolation" page of Windows Security, I am not sure how "safe" this is in terms of Windows 11's own security, but at least it lets Workstation Pro 16 run at full speed once more.