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You are running a Windows Presentation Foundation (WPF) application in the Visual Studio 2008 Service Pack 1 (SP1) IDE. When you use the WPF designer or you rebuild the application, the IDE stops responding. Additionally, you receive the following message in the notification area:

Microsoft Visual Studio is BusyWhen this problem occurs, you have to end the devenv.exe process in the task manager and then restart the Visual Studio IDE.


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

To download this hotfix from the MSDN Code Gallery, visit the following Microsoft Web site:
Note The MSDN Code Gallery displays the languages for which the hotfix is available. If you do not see your language listed, it is because the Code Gallery resource page is not available for that language.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:


You must have Visual Studio 2008 Service Pack 1 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The global version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

File name

File version

File size







06-May- 2009






06-May- 2009




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

More Information

This hotfix also fixes the following problems that are introduced by the hotfix that is described in KB article 958017, or that are introduced by Silverlight 2 Tools for Visual Studio 2008 Service Pack1:

  • Additional entries appear in the XAML IntelliSense feature. However, these entries do not match your context.

  • You cannot use Choose Items to add WPF items to your toolbox unless you deleted the WpfComponents.cache file in your application data folder.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

958017 A hotfix rollup is available for WPF Designer

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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