The Module DLL kerbauth.dll failed to load. The data is the error. (The Module DLL C:Program FilesMicrosoftExchange ServerV14Binkerbauth.dll failed to load. The data is the error.)


I thought of writing this blog since i saw this issue on a few of cases.

Symptoms

========================

After re-installing Exchange Server, you may see 503-Service unavailable while browsing Exchange Management Console or “Default Website”

At times, you may also see that the request keeps spinning in the browser and response does not comes back at all.

You may see following entry in the application event logs

The Module DLL E:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll failed to load.  The data is the error.

 

Cause

=======================

Reason for 503-Service unavailable is that application pool is stopped but the actual reason is something else has caused the app pool crash and finally leading to stopped state. This application pool was stopped because of by default 5 consecutive exceptions within 5 minutes which is default behavior for IIS worker process.

This issue starts happening if during re-install of the Exchange Server, you select a different location to install.

When Exchange server was installed for the first time, it registers its custom modules with IIS and for this it makes entries in the IIS root config file i.e. applicationHost.config at this location C:\Windows\System32\inetsrv\config. These enties are made under the <globalmodules> section. You will see one such entry for kerbauth.dll.

  <add name="kerbauth" image="C:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll" />

While uninstalling the Exchange from the server, these entries might not be removed from the applicationHost.config. Issue starts when while re-installing the Exchange, the installation drive is changed. So such dlls will be copied at some other location while this entry is not modified in the applicationHost.config file.

While accessing the website, IIS will try to load this dll from the old path C:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll while this dll is not there and exists at some other path now.

While loading this dll, IIS will not be able to locate this and will throw an error and you must see an entry like following in the application event logs.

Log Name:      Application

Source:        Microsoft-Windows-IIS-W3SVC-WP

Date:          9/5/2013 11:03:23 AM

Event ID:      2280

Task Category: None

Level:         Error

Keywords:      Classic

User:          N/A

Computer:      STAL-EXCH01.stalber.loc

Description:

The Module DLL E:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll failed to load.  The data is the error.

Event Xml:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">

  <System>

    <Provider Name="Microsoft-Windows-IIS-W3SVC-WP" Guid="{670080D9-742A-4187-8D16-41143D1290BD}" EventSourceName="W3SVC-WP" />

    <EventID Qualifiers="49152">2280</EventID>

    <Version>0</Version>

    <Level>2</Level>

    <Task>0</Task>

    <Opcode>0</Opcode>

    <Keywords>0x80000000000000</Keywords>

    <TimeCreated SystemTime="2013-09-05T15:03:23.000000000Z" />

    <EventRecordID>160043</EventRecordID>

    <Correlation />

    <Execution ProcessID="0" ThreadID="0" />

    <Channel>Application</Channel>

    <Computer>STAL-EXCH01.stalber.loc</Computer>

    <Security />

  </System>

  <EventData>

    <Data Name="ModuleDll">E:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll</Data>

    <Binary>7E000000</Binary>

  </EventData>

</Event>

If IIS fails to load this dll, it keeps throwing this error message and then finally will stop the application pool. So we start getting 503-Service unavailable error.

Resolution

==================

To resolve this issue, you need to manually change the path of kerbauth.dll to the latest path where exchange has been installed during reinstall.

1. Open ApplicationHost.config file at this path C:\Windows\System32\inetsrv\config

2. Find the entry for kerbauth.dll like following

<add name="kerbauth" image="E:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll" />

3. Change the path for this dll as per the latest location of the Exchange Server installation files.

<add name="kerbauth" image="C:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll" />

 

Please feel free to provide the feedback on this post. Let me know if you have any concerns.

Comments (30)

  1. Austin Velasquez says:

    Thanks for help i has more than 2 weeks find solution for this issue. and with this procedure work for me.

    Best Regards

  2. Sinisa says:

    THANKS! Brilliant! In my case, I was re-using two 2012 Servers that previously ran Exchange 2010. I thought I removed all 2010 traces, but I guess not. This location was referring to "14" instead of "15" in the path.

  3. Arun Shetty says:

    Thanks for the article. This saved a lot of my time.

  4. Leonard says:

    Thanks man! You just saved my life!

  5. Steve says:

    Similar problem but in reverse. I uninstalled Exchange Server 2010 from this server, rebooted, and left it for a couple of days to see if it threw up any errors.

    This error was coming up basically every second.

    I removed the entry to that file, reset IIS and all good.

    Thanks.

  6. Mark says:

    Can you just simply remove it? MS Exhange no longer exist..

  7. Thanks for the feedback guys. I am happy that It helped.

    Mark,

    I apologize but I didn't get you.

    Thanks

    Gaurav

  8. Nick says:

    Thank you very much 🙂 Solved my issues!

  9. Nick says:

    @Mark, yes you can. I just removed that one line in the config file, restarted the IIS service and it works absolutely fine.

  10. Ram reddy G says:

    Similar problem, I uninstalled exchnage 20ao and changed the Drive letter of Exchange server path and re-installed the Exchange. Then I got this roblem.This error was

    coming up basically every second.

    I follwed this article and solved the issue.

    Thanks

  11. Kim Kirchhoff says:

    Perfect solved my problem… no issues now.

  12. Harold Bleemel says:

    YES! This worked for me by removing the line from the config file. Once I did the website started working again!

  13. Naren says:

    excellent i was having couple of issues because of this WinRm issue, you saved my lot of time, it resolved almost all issue winch are related to remote connectivity for third-party installations even. thanks for the super blog..:)

  14. @Thanks Austin, Sinisa, Arun, Mark, Nick, Ram, Kim, Harold, Naren

    Felling happy that it helped.

  15. Mercedez says:

    OMG! you are a genius. Thank you so muchhhhhhhhhhhhhhhhh

  16. Eduardo Garcia says:

    Gracias! me sirvio de guia para resolver mi problema.!

    Saludos.

  17. Eduardo,

    Su bienvenida

    Thanks Mercedez

  18. Pashupathinath says:

    Thanks alot. It resolved the issue.

  19. Mahendra Reddy says:

    I have no words to appreciate you. I was breaking my head for 2 long days to resolve this issue.

    thank you very very much..

  20. Kanishka says:

    Superb information in this blog.

    I was facing the exact same issue, followed the steps exactly as you have listed but still unable to resolve the problem.

    Please tell me if I'm missing something here.

  21. Michael F. says:

    Superb!
    Resolution does the trick.
    Thx so much.

    Michael

  22. Mike Ulloa says:

    Excellent post. To the point and solved my issue quickly.

  23. Maarten van Duinkerken says:

    Great thank you!

  24. Rob says:

    Thanks for the fix, I had a failed install and could not connect to the server via OWA or Powershell, couldn’t uninstall due to mailboxes being present and not way to remove them. Noticed that the file kerbauth.dll was pointing to the wrong location. the fix work perfectly.

  25. Sachin Pathare says:

    This solution fixed my issue for Exchange 2k16, Thanks a lot !!

  26. Kingsley Ekwere says:

    Very helpful article, help out in my exchange 2016 live environment deployment

  27. Anand says:

    Tt worked, thanks for the info

    1. Welcome. Don’t forget to rate it then. 🙂

  28. pierluigi says:

    GREAT! it worked for me, thank you!

  29. Dilip Sasikumar says:

    Thanks a lot for this excellent article Gaurava!!

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