(Service Unavailable) Could not load all ISAPI filters for site/service. Therefore startup aborted.


After running the Sharepoint products and technologies configuration wizard successfully, the central administration site page opens up.

( We were installing MOSS 2007 on 64 bit machine)

But in my case it was giving the following error

“Service Unavailable”

Checking into event log gave the following information

Could not load all ISAPI filters for site/service. Therefore startup aborted.


ISAPI Filter ‘C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_filter.dll’ could not be loaded due to a configuration problem. The current configuration only supports loading images built for a AMD64 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.

Searching for it the solution that I found was the following

// Disabling the 32bit mode for your web site.

cscript C:\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0

and then the following

// Registering ASP.NET 2.0 as the default framework for that web site

aspnet_regiis.exe -i

This resolved the issue for us!!


Author: Nishant Rana

I love working in and sharing everything about Microsoft.NET technology !

24 thoughts on “(Service Unavailable) Could not load all ISAPI filters for site/service. Therefore startup aborted.”

  1. Hi
    when I perform second ins this error will apear:
    “The error indicates that IIS is in 64 bit mode, while this application is a 32 bit application and thus not compatible.”


  2. You’re a savior. Customer installed some 32-bit software on a 64-bit server. After the offending software was removed and these steps were take they are back up and running.


  3. Worked for us!

    We installed Globe Software Atlas 4.0 for Dynamics which reconfigured the framework for our defualt website. Runnning the solution above set the framework BACK to v2.0.50727


    what we ran to fix:
    C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727>aspnet_regiis.exe -i


  4. This is truly a great post and it saves my time! Thank you very much for it. I have extensive knowledge in running Sharepoint 3 on Windows Server 32-bit version, but when it comes to Windows 64-bits version, I face several problems.

    Recently, I am using Windows Server 2008 R2 Edition 64-bit (the “server” version of Windows 7) and I always face this problem when trying to install Sharepoint for the first time. The error message: “IIS in running 32-bit emulation mode, please fix this error to continue” truly makes me think hard as to why Windows OS 64 bits can have an IIS running in 32-bits mode! Geez……..!!

    I then contacted my current host, asphostcentral.com, and they refer me to your article for details. This truly saves my time and everything. You are the BEST and I certainly look forward to more of your thoughts on WSS problems.

    Again, Thank you.


  5. I trust the above was helping, but here’s what all I had to do for Windows 7:
    1. The above…
    2. Removed .Net 1.1 with dotnetfx_cleanup_tool
    3. Removed .Net 2.0
    4. Removed .Net 3.5 from the tools turn off features
    5. Added back in .Net 3.5
    6. (and the winner is)
    Open IIS Manager
    Click on the machine name so it shows the icons for the top level
    open ISAPI Filters from the IIS group
    change the Executable from:

    Basically added the 64, where it should be. Lots of frustration for a simple resolution.

    Good Luck.


    1. I installed Helicon Ae engine, and getting the same error,In my system I couldn’t find the framework64 , It has only Framework, What should I do,??


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