All ASP.NET applications run in the same worker process after you upgrade a Windows XP-based computer that is running IIS 5.1 to Windows Vista

You install Microsoft ASP.NET 1.1 and Microsoft ASP.NET 2.0 on a Microsoft Windows XP-based computer that is running Microsoft Internet Information Services (IIS) 5.1. In IIS 5.1, you host an ASP.NET 1.1 Web application and an ASP.NET 2.0 Web application. You upgrade the Windows XP-based computer to Windows Vista.

After you upgrade the computer to Windows Vista, all ASP.NET applications run in the same worker process. For example, both the ASP.NET 1.1 application and the ASP.NET 2.0 application run in the same application pool in IIS 7.0.

Additionally, a Web application may not work as expected after you upgrade the computer to Windows Vista.

Notes

• ASP.NET 1.1 is installed as part of the Microsoft .NET Framework 1.1 and the Microsoft .NET Framework 1.1 Service Pack 1 (SP1).
• ASP.NET 2.0 is installed as part of the Microsoft .NET Framework 2.0.

This problem occurs because Web applications are running in the ASP.NET process model.

To resolve this problem, create an application pool for each Web application. Then, move the Web application to the application pool that you want. To do this, follow these steps:

1. Click Start
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   , type inetmgr in the Start Search box, and then click Inetmgr in the Programs list.
   
   
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   If you are prompted for an administrator password or confirmation, type the password, or click Continue.
2. In Internet Information Services (IIS) Manager, expand the computer that you want to configure.
3. Right-click Application Pools, and then click Add Application Pool.
4. Type a name for the new application pool, click the .NET Framework version that you want to use, and then click OK.
5. Expand Default Web Site.
6. Right-click the Web application that you want to move, and then click Advanced Settings.
7. Click Application Pool, click the application pool in the Application Pool box, and then click OK.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

To prevent this problem, configure the Web application to run in high isolation mode before you upgrade the computer to Windows Vista.