[SOLVED] I can't update Windows 11 from 23H2 to 24H2 ?

[cyph07x]

Hi,

First time posting.
I am just really puzzled by this issue.

I work in a company, and I have 4' Hyper-V 2019 bare-metal servers, 2 old servers with dual Xeon Silver 4110, and 2 newish servers with dual Xeon Silver 4310 CPUs (both with 128GB RAM)
I have several Windows Server 2019 VMs and a few Windows 10 and Windows 11 VMs.

However, I am trying to update Windows 11 from 23H2 to 24H2 and boom, I get this:

This PC's processor doesn't support a critical feature (PopCnt)
This PC's processor doesn't support a critical feature (SSE4.2)

But these are newish CPU (the 4310) from 2021,
where Intel states:
Instruction Set Extensions
Intel® SSE4.2, Intel® AVX, Intel® AVX2, Intel® AVX-512

Even the 2017 CPUs 4110 have the same instructions.
Instruction Set Extensions
Intel® SSE4.2, Intel® AVX, Intel® AVX2, Intel® AVX-512

These are Dell PowerEdge servers,
Is there some BIOS setting to "enable" SSE4.2? or some configuration I need to do so I can get 24H2 installed as VM's on these servers?

I am just confused. - Thanks Microsoft!

 

[das_stig]

W11 are they gen2 VMs, so support all the latest features/requirements ?

 

[cyph07x]

When I create new VM's I always use Gen2. So yes.

 

[BFG-9000]

Those servers do meet all of the requirements for installing Win 11 24H2 directly, but the problem is the VM may not expose/pass through the required features with default settings.

With Gen2 the vCPUs are synthetic, not emulated and you may have better luck setting a specific processor model in the VM's config file rather than having the CPU in passthrough mode, particularly if the CPU is newer than the Hyper-V version as with your "Skylake-Server IBRS" processors. Note that you may not only have to downgrade the setting to a consumer-grade CPU family but also to an older, previous-gen one to get it to work by trial-and-error--but don't go too old or you will lose the Win 11 compatibility entirely.

 

[Ralston18]

@cyph07x

FYI:

https://community.intel.com/t5/Proc...ot-support-the-POPCNT-instruction/m-p/1610165

https://computermesh.com/how-to-know-if-cpu-supports-the-sse2-sse3-sse4/

Both links are simply starting points for you to delve a bit deeper into the details.

Likely that there are any number of reasons because of differences in ages and versions of the various servers.

There may not be a single solution.

 

[cyph07x]

I had to install Windows Server 2025, that comes with updated Hyper-V.

24H2 doesn't support Hyper-V 2019 server, or Hyper-V doesn't fully support the features that 24h2 requires.

Anyway, all sorted.