Article ID: 4001, created on Mar 13, 2008, last review on May 10, 2014

  • Applies to:
  • Plesk for Windows


When you retrieve the properties for a website or virtual directory in Microsoft Internet Information Services (IIS) Manager, the ASP.NET tab of IIS Manager does not appear. Alternatively, the Edit Configuration button on the ASP.NET tab is disabled.


This problem occurs when any one of the following conditions is true:

You are using the 32-bit version of IIS Manager on a 64-bit computer.
You are using IIS in Microsoft Windows-32-on-Windows-64 (WOW64) mode.
You have set the Enable32bitAppOnWin64 property to True in IIS. This setting lets IIS run in 32-bit mode on a 64-bit computer.

WOW64 is an emulation layer that enables 32-bit Windows-based applications to run seamlessly on 64-bit computers.

his problem occurs because the 32-bit version of IIS Manager is incompatible with 64-bit computers that use Microsoft ASP.NET.

This problem can also occur because the 64-bit version of IIS Manager cannot load the 32-bit Aspnet_isapi.dll file as a native 64-bit file. Additionally, the 64-bit version of IIS Manager cannot load this file in WOW64 32-bit mode.


To work around this problem, use the 64-bit version of IIS Manager. Also, do not use IIS Manager in WOW64 mode.


Please see original Microsoft article here

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