FIX: Error message when you set the encoding property to UTF8 and run a Web service to send messages that contain invalid characters: "Unable to translate Unicode character ‘invalid character string’ at index ‘index_number’ to specified code page"

You create a custom encoder fallback to handle encoding conversion failures for input messages in a Web service. If an input message contains invalid characters that cannot be converted, a substitute string is encoded instead of the invalid characters. Then, the encoding operation continues converting the rest of the message. However, when you set the encoding property to UTF8 and run a Web service to send messages that contain invalid characters, a System.Text.EncoderFallbackException exception occurs and you receive the following error message:

This problem occurs because the Web service does not start the custom encoder fallback. Instead, the Web service starts the EncoderExceptionFallback system class that throws the System.Text.EncoderFallbackException exception.

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 the problem described in this article. 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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

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: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must have .NET Framework 3.0 Service Pack 2 (SP2) or .NET Framework 3.5 Service Pack 1 (SP1) installed to apply this hotfix.

Restart requirement

You don't have to restart the computer after you install the hotfix if no relative instance is in use.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English 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.

Windows Vista SP1, Windows Server Core and Windows Server 2008, x86-based versions

Windows Vista SP1, Windows Server Core and Windows Server 2008, x64-based versions

Windows Server Core and Windows Server 2008, Itanium-based version

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

When a Web service sends an XML-based message, an encoding operation maps the Unicode characters to encode sequences of bytes according to the encoding property. When the encoding operation fails, the service calls an encoder fallback to handle the failure.

For more information about the EncoderFallback class, visit the following Microsoft Web site: