Windows Server 2019 Hyper-V On DELL UEFI generation 12 Servers boot loop issues


Windows Server 2019 Hyper-V On DELL UEFI generation 12 Servers boot loop issues are fixed. As many of you experienced Windows Server 2019 installed on UEFI mode BIOS setting on DELL generation 12 hardware (R620, R720) tends to send the server into a boot loop. This was a surprise as it worked well during the previews. The same was reported and experienced on DELL generation 11 hardware. You can read about it in various places like Windows Server 2019 Datacenter boot loops after enabling Hyper-V, Windows server 2019 fails after hyper-v role install and
Windows Server 2019 Boot-loop Problems…

In the end, it was an issue that Microsoft would have to fix and they did in KB4476976. Before that you would have to revert to BIOS to get Hyper-V to work on a generation 12 DELL Server. Today I am happy to report that the Windows Server 2019 Hyper-V On DELL UEFI Generation 12 servers boot loop issues have been fixed

Install using the original MSFT ISO

Use SW_DVD9_Win_Server_STD_CORE_2019_64Bit_English_DC_STD_MLF_X21-96581.ISO, not the earlier one that was retracted.

Clean Install

Install Windows Server 2019 and update it fully, including the latest CU, KB4476976 at the time of writing. Only then add the Hyper-V role.

In place upgrade

In-place upgrades work by removing the Hyper-V role, doing an in-place upgrade and then updating it fully up to KB4476976. Afterwards, add the Hyper-V role again. If the nodes are in a cluster you’ll need to evict it from the cluster and add it again before going through the above process for an in-place upgrade.

Install using a custom built ISO

I refer you the blog of my fellow MVP Philip Elder to learn how to do that. In this case, there is no need to remove the Hyper-V feature like in case of an in-place upgrade or run update after doing a clean install as the correct bits are in the ISO you created to install or upgrade the OS.


I’m happy I can finally use my lab hardware again and even upgrade some production servers. Do note that DELL generation 12 servers do not officially support Windows Server 2019. I will try this out on a generation 11 server when I get the chance.

19 thoughts on “Windows Server 2019 Hyper-V On DELL UEFI generation 12 Servers boot loop issues

  1. Easiest fix for this is to go into bios, change the CPU support to disable virtualisation features. The server should boot right away 🙂 Nasty bug indeed!

      • I am seeing the issue now on R740XD with UEFI install of 2019. Able to reboot totally fine until Hyper-V role is enabled, then wont go past the loading windows screen. I have raised a Dell call, hopefully that will help. 2016 is totally fine on the box.

        • That is mildly disconcerting. In that case, I would certainly try without the Hyper-V role installed and patch the server completely and verifying a good boot before installing the Hyper-V role again to see if that helps. I take you are up to date with BIOS etc?

          • Yep, thats all up to date. When I try to install the most current firmware from dell, I get a message saying its already installed. So, I am sure that is fine.

            The only info I can see online (others seem to have similar issues), is to switch to BIOS mode from UEFI, install the OS to MBR etc… which I dont really want to do.

          • I would not like to do that either. Wait what DELL says. But it is not a boot loop, it hangs after the windows loading screen. The most recent CU I have on some R740 (not XD) is KB4507469. We have seen no issues bare long reboot time after that update.

  2. I have another two R740XD coming in the next few days, Ill keep this one on 2016 and test with those when they are here and see what Dell says. Thanks 🙂

  3. Hi,
    Got this working fine by disabling virtualization, installing updates and enabling virtualization again. However restarting the server from windows gracefully shuts it down and I have to use iDrac to turn it back on. Any fixes for this please?

    • With newer ISO’s this should no longer be an issue. I did not need to use this trick with ISO’s release later, after that hotfix. Do you use an old one or a recent one?

  4. Hi,

    Thanks for getting back to me. I used the latest Hyper V 2019 server. Maybe I will try the very last full server 2019 instead.

    Does your server reboot correctly or shutdown?


    • You are welcome. Yes it did back in the new with updates ISOs. I do not have a gen 12 anymore to test with the most recent ISOs.

  5. Hi,
    Tom, did you get a fix for shuttingdown your server instead of restart?
    I have everything working fine but when the system should restart it turns of. It happens when Windows restart because of an update or even if I choose to restart the server it then shuts down.
    I found some on the Internet said that if use of MBR instead of GPT on the partition Windows is on then it reboots fine.
    I think I will test that.


    • No, the ideas are in the comments or blog post itself. Do make sure you have a recent BIOS installed and disable Hyper-V to see if this helps. Use a recent ISO.

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