IIS: Running multiple versions of the Framework in ASP.NET

IIS 5 manage ASP.NET within processes called aspnet_wp.exe, there is one per version of the framework. (v1.0, v1.1 and v2.0); IIS 6 provide a new feature called Application Pool and every pool has a process called w3wp.exe and asp.net will run into this process.

While multiple versions of the framework can co-exist on the same server, they can't co-exist in the same process. If you attempt to run multiple versions of the framework at the same time in the same process, the 2nd version that tries to run will fail with the following error:
Server Application Unavailable

The event viewer will log the following event: "It is not possible to run two different versions of ASP.NET in the same IIS process. Please use the IIS Administration Tool to reconfigure your server to run the application in a separate process."

The solution is pretty easy, simply create a new application pool and move the site on that pool.
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Vittorio Pavesi

6comments

  1. Anonymous
    3:28 PM

    okay, now how can i create a new app. pool?

  2. YOU CAN FIND OUT HERE ON HOW TO CREATE AN APPLICATION POOL

    http://kikosantos.wordpress.com/2006/06/15/running-multiple-version-of-net-framework-in-iis-60/

    - Nanda

  3. Anonymous
    2:38 PM

    It really helped me. Thank you. I appreciate your effort.

    Srini.

  4. Nick P.
    7:52 PM

    I'm pleased to announce the public availability of my IIS Metabase Analyzer which will help you locate and resolve this issue. It is available here:

    http://allegiance.chi-town.com/IisMetabaseAnalyzer.aspx

    Please let me know if you find it useful.

    Thanks,
    Nick.

  5. thanee.n
    3:09 AM

    hi Nick P., thanks for the analyzer tools, it's very helpful and fixed my problem.

  6. Anonymous
    7:38 AM

    Thanks mate
    Valuable information
    This saved me quite some time :-)

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