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Windows Deployment Services (WDS) 2012 R2: Error 0xc0000001 when booting from image via PXE

by | Jul 28, 2014 | Administration | 55 comments

This entry has been published on 2014-07-28 and may be out of date.

Last Updated on 2014-07-28.

Older Mainboards seem to have a problem with the TFTP block size setting.

When you try to boot the image via PXE, you see the white status bar filling up, but suddenly the error appears: “0xc0000001, a required devices isn’t connected.”

In Windows Event Log, you might see event ID 4101 with error code 1460, source Deployment-Services-Diagnostics.

I tried several hints from various forums with no success.

In the end, the solution for me were the following steps:

  1. Open WDS
  2. Right-click your server in the left pane and open properties.
  3. Open tab “TFTP” and change the maximum block size to e.g. 1024.
  4. Restart your WDS server.

You might have to experiment with the block size value. In my case, it first didn’t work with 1024, but on the second try it suddenly worked and Windows Setup was able to boot.

55 Comments

  1. Pablo
    Pablo on 2015-06-01 at 01:56

    It works for me, but only after uncheking “Enable Variable Windows Extension” too (I use VirtualBox for this test).

    Thanks for your help!!

    Pablo.

    • Anton Stern
      Anton Stern on 2015-08-10 at 11:53

      great !!! thanks a lot helped me too uncheking “Enable Variable Windows Extension” using VirtualBox as well

    • Phil
      Phil on 2016-11-15 at 11:38

      Nailed it!!! Thanks so much! (Virtual box, Uncheck ‘Enable Variable Windows Extension’)

    • shravan
      shravan on 2019-04-03 at 12:37

      Hello Pablo,

      thanks, man it got worked for me, I am facing this issue from the past two days.
      anyway once again ThQ

    • Clive Marshal
      Clive Marshal on 2019-04-06 at 07:25

      Thank you so much. It is working fine.cheers!!!

    • Timothy Ju
      Timothy Ju on 2019-04-10 at 16:03

      I entered 1024 and rebooted and it still didn’t work with 2 different laptops. So, turned off “enable variable extension” without rebooting the server and it worked for those 2 laptops!

      • Timothy
        Timothy on 2019-04-10 at 16:15

        Oh, and should have added this was on Win Server 2016 WDS.

  2. faisal
    faisal on 2015-07-04 at 15:00

    Thanks alot man. its work for me i was stuck in this error for few days. and you get me out good work.

  3. ketah
    ketah on 2016-02-21 at 19:45

    Hi, thanks for the tips I was going to get mad with this.
    I unchecked the Variable windows extension and set the TFTP to 1024 and then it works ! (virtualbox too)

    Thanks again !

    • salim
      salim on 2016-05-26 at 19:42

      Hi,
      I have the same problem.
      Can you tell me where find the box variable windows extention that i have to unchecked please.???

      • administrator
        administrator on 2016-06-01 at 11:04

        It’s also within the TFTP tab.
        Maybe you use another Windows Edition like 2008 (R2)? The tab is not available there, you might have a chance to change it via registry keys etc.

        • salim
          salim on 2016-06-02 at 18:22

          Hi i found it and it’s work now. Thanks
          (just i use windows server 2012 r2.)

  4. SamCook
    SamCook on 2016-08-24 at 05:50

    Thank you, it worked for me too.

  5. Ollie Townsend III
    Ollie Townsend III on 2016-10-27 at 18:52

    Yet another thank you! Only took an hour of trying official Microsoft/Dell websites before abandoning it and going straight to Google which lead me to your site. This would have taken a lot longer if you hadn’t posted this. Much appreciated!

  6. Patrice
    Patrice on 2016-12-20 at 15:16

    Thank you so much.
    Uncheck ‘Enable Variable Windows Extension’ in the TFTP tab on WDS Server solved the problem.

  7. Ammar
    Ammar on 2017-04-03 at 12:47

    Just uncheking “Enable Variable Windows Extension” solve it

  8. Uros
    Uros on 2018-08-02 at 06:18

    Unchecking “Enable Variable Windows Extension” solve it for me too, thank you very much.

  9. Nes
    Nes on 2018-08-08 at 17:21

    Awesome this worked for me too.(using virtual box)

    can someone advise, when adding the install.wim & boot.wim file via virtual box and selecting disk image (which is on local machine (E:Drive ) when selecting these files virtual box responds with error VBOX_E_IPRT_ERROR (0x80BB0005).

    i managed to get around this but not able to now, can someone advise please.

    Many Thanks

  10. Vipin Kumar
    Vipin Kumar on 2019-03-20 at 08:43

    Nailed IT Bro!!!!
    thank its works for me.
    thank you so much

  11. Mika
    Mika on 2019-03-20 at 12:41

    Thanks!

    This solved also my issue with Server 2016 as WDS, and when using UEFI PXE boot in vSphere 6.0 when VM uses either E1000 or VMXNET3 vNIC.

    Before those changes I could only PXE boot using BIOS but UEFI always failed with the 0xc0000001 error.

    I also tried earlier to change ramdisktftpblocksize in default.bcd to 4096 but that change didn’t fix the issue.

    Awesome job!

  12. Andy
    Andy on 2019-03-20 at 17:22

    This fix is still making WDS function correctly on Server 2016 when it randomly stops. Thanks so much…

  14. Brian
    Brian on 2019-03-21 at 14:25

    This worked for me as well on a 2016 wds server built in VMWARE. Does anyone know why this error suddenly occurs? One of the techs injected a new nic driver into the server and it all stopped working until I did this fix. Not sure how one relates to the other.

  15. Brian
    Brian on 2019-03-21 at 14:28

    This worked for me as well on a 2016 WDS server built on a vmware host. Does anyone know why this happens all of a sudden? On of the Techs here injected a new nic driver into the boot.wim and everything stopped working until I applied this fix. I don’t see how one relates to the other.

  16. Dave W
    Dave W on 2019-03-22 at 12:52

    Spend a day trying to sort this…..read this fixed. Thank You

  17. techguy
    techguy on 2019-03-22 at 13:17

    @Brian:

    Even stranger for me: We have changed absolutely nothing. Yesterday I was applying patches on our WDS-Server (2012 R2):
    KB4489873
    KB4489881
    KB4489883
    KB4489488

    I’m quite sure that those patches missed it up. I can confirm that Deployment worked yesterday. After applying the patches I’ve had to set te described settings within the TFTP-Settings. But it is still not working with the same error….

  18. techguy
    techguy on 2019-03-22 at 14:55

    Ok sry I didn’t saw the comment explaining that you need to uncheck the „Enable Variable Windows Extension“ option. After unchecking this option, wds is working again with a tftp max bloc size of 1456

  19. ayoubW12
    ayoubW12 on 2019-03-23 at 17:52

    Tnx a lot Bro
    its works for me by unchecking “Enable Variable Windows Extension” (using ESXI Server)

  20. Oleg Montau
    Oleg Montau on 2019-03-25 at 14:27

    You saved my day. Unchecking “Enable Variable Windows Extension” fixed the issue.
    Everything was working until I installed March Microsoft updates. I have WDS on Windows Server 2012 R2. Thank you again.

  21. kantholy
    kantholy on 2019-03-26 at 16:47

    same here, 2019-03 Windows Updates broke the WDS Server.
    After unchecking the “Enable Variable Windows Extension” and restarting the WDSServer Service it’s working again!

  22. Zee Ali
    Zee Ali on 2019-03-26 at 17:50

    You saved my day. Thanks a lot

  23. Joe Reid
    Joe Reid on 2019-03-27 at 09:13

    I am studying computing at college and could not get WDS to deploy on my computer in the house until I seen this. Been trying for three days. Thanks for this.

  24. Nathan Cook
    Nathan Cook on 2019-03-27 at 10:33

    The above fixed it for me to. WDS seeming to break after installing the March 2019 Windows Updates. It was fine up until this point.

  26. Jason Soja
    Jason Soja on 2019-03-28 at 18:45

    From Support Document found at https://support.microsoft.com/en-us/help/4489881/windows-8-1-update-kb4489881

    After installing this update, there may be issues using the Preboot Execution Environment (PXE) to start a device from a Windows Deployment Services (WDS) server configured to use Variable Window Extension. This may cause the connection to the WDS server to terminate prematurely while downloading the image. This issue does not affect clients or devices that are not using Variable Window Extension.
    To mitigate the issue, disable the Variable Window Extension on WDS server using one of the following options:

    Option 1:
    Open an Administrator Command prompt and type the following:

    Wdsutil /Set-TransportServer /EnableTftpVariableWindowExtension:No

    Option 2:
    Use the Windows Deployment Services UI.

    Open Windows Deployment Services from Windows Administrative Tools.
    Expand Servers and right-click a WDS server.
    Open its properties and clear the Enable Variable Window Extension box on the TFTP tab.
    Option 3:
    Set the following registry value to 0:

    “HKLM\System\CurrentControlSet\Services\WDSServer\Providers\WDSTFTP\EnableVariableWindowExtension”.

    Restart the WDSServer service after disabling the Variable Window Extension.

    Microsoft is working on a resolution and will provide an update in an upcoming release.

  27. Ant
    Ant on 2019-03-29 at 20:08

    Thank you Guys ! Awesome, its worked by uncheking “Enable Variable Windows Extension” & change the maximum block size to 1024.

  28. MS Hater
    MS Hater on 2019-04-02 at 22:02

    this is so microsoft to break something like this with a patch and make me spend 8 hours troubleshooting my drivers only to find this article which leads me to a checkbox. F*#@%

  29. Sara
    Sara on 2019-04-03 at 17:28

    I have WDS server 2016 it is working for me. Thank you

  30. Eike
    Eike on 2019-04-04 at 10:19

    Windows 10 Hyper-V Host and Server 2016 WDS virtualised – unchecking “Enable Variable Windows Extension” and it works like a charm. Thanks!

  31. Mick
    Mick on 2019-04-06 at 18:29

    Unchecking “Enable Variable Windows Extension” in WDS worked for me too. Running Win Server 2012 R2 here. I just updated MDT to 8456 and ADK.

  32. Bob
    Bob on 2019-04-12 at 14:41

    Nicely done Pablo, Jason Soja! Saved me a lot of pain.

  33. Mike Coleman
    Mike Coleman on 2019-04-16 at 13:29

    Unchecking the enable variable windows extension on the TFTP tab worked for me with Windows Server 2016, great job finding this!

  35. Abel Robles
    Abel Robles on 2019-04-29 at 23:08

    Thank you. It works for me too. Windows Server 20016.

  37. Nelson
    Nelson on 2019-05-06 at 12:42

    Uncheking “Enable Variable Windows Extension” worked for imaging WDS wim files in Server 2012 but not for WDS does not start. Still going to try figure this out on Server 2019.

    Thanks for the help guys

  38. Eli
    Eli on 2019-05-09 at 19:23

    Uncheking “Enable Variable Windows Extension” worked for us as well. Thanks!

  40. Zak
    Zak on 2019-07-02 at 00:49

    I am still getting same error – after disabling Variable windwos extension.

    March updates applied.
    July updates applied still no luck

    Any suggestions?

  41. matt
    matt on 2019-07-18 at 16:25

    I am in the same boat.
    Server 2019
    Uninstalled all questionable updates, and unchecked Enable Variable Windows Extension
    Changed block size to 1456 , 16384 , 0 , and max.

    Please halp.

    • Gio
      Gio on 2019-08-14 at 11:08

      I’m also having the same issue. Changing block sizes to all the recommended, checked and unchecked variable windows extension – nothing works – server 2016
      Even changed the values through bcdedit – still nothing . did you fix it in the end?

      • Giorgi
        Giorgi on 2019-08-16 at 10:19

        Same issue exist with me, it doesnot works! looking for new solution

  42. Scatman
    Scatman on 2019-07-29 at 10:28

    This doesnt work anymore 😐

    unbless and bless again doesnt works too

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