When you use Windows Media Player and you try to play an .avi file, you may receive any of the following error messages: The following error messages typically display the Four Character Code (FourCC) identification in the error message:

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This behavior can occur if the .avi was created by using a codec that was not installed on the host computer, and the codec is not available on an update site. This behavior can also occur because the file encoding for the .avi file is unsupported.

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Method 1

Windows XP users

1.	Click Start, point to Run, type mplay32.exe, and then press ENTER.
2.	Click Open on the File menu, locate the .avi file that you want to play, and then drag the file to Windows Media Player.
3.	When you receive the error message that specifies the FourCC identification, be aware that FourCC identification. For example, if you are using a VCR2 codec from ATI, "vids:vcr2" is the FourCC identification.

Note The FourCC identification that you receive may be in the vidc.iv50 format. If the FourCC identification displays "vidc" in the identification, the file contains video. The last four characters in the FourCC vidc identification specify the codec that you must have to play the file.

You must obtain the codec that you must have to play the .avi file from the appropriate manufacturer. Be aware that not all manufacturers provide their codecs for you to download.For information about how to contact the manufacturer, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

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Method 2

Windows Vista users

1.	Double-click the .avi file that you want Windows Media Player to play. You receive an error that resembles the following: Windows Media Player encountered an error. Click the icon for more information
2.	Click Error Details to receive the following message: A codec is required to play this file
3.	Click Web Help to display information about the missing codec and the corresponding link if the codec is available to download.

Windows XP users who have Windows Media Player 9, Windows Media Player 10, or Windows Media Player 11

1.	Double-click the .avi file that you want Windows Media Player to play.
2.	Under Now Playing, right-click the exclamation mark in front of the file name, and then select Error Details.
3.	Click Web Help to display information about the missing codec and the corresponding link if the codec is available to download.

Note If you still have problems with Windows Media Player, you might want to ask someone for help or contact support. For information about how to contact support, visit the following Microsoft Web site:

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Be aware that .avi files can contain several different audio or video formats. To play an .avi file, you must use the .avi file player and the relevant codec file to decompress the .avi file. For more information, click the following article number to view the article in the Microsoft Knowledge Base: For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base: Microsoft does not support playing .avi files that were created by using the MPEG4 version 3 codec.

To make sure that you have the latest information to troubleshoot issues with Microsoft Windows Media Player 11 for Windows Vista, Windows Media Player 11 for Windows XP, Windows Media Player 10, and earlier versions of Windows Media Player, we recommend that you visit one of the following Microsoft Web sites.

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Windows Media Player 11 for Windows Vista

For information about how to troubleshoot Windows Media Player 11 for Windows Vista issues, visit the following Microsoft Web site:

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Windows Media Player 11 for Windows XP

For information about how to troubleshoot Windows Media Player 11 for Windows XP issues, visit the following Microsoft Web site:

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Windows Media Player 10

For information about how to troubleshoot Windows Media Player 10 issues, visit the following Microsoft Web site:

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Earlier versions of Windows Media Player

For information about how to troubleshoot issues with earlier versions of Windows Media Player, visit the following Microsoft Web site: For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base: If these Microsoft Knowledge Base articles do not help you resolve the problem, or if you experience symptoms that differ from those that this article describes, please search the Microsoft Knowledge Base for more information. To search the Microsoft Knowledge Base, visit the following Microsoft Web site: Then, type the text of the error message that you receive, or type a description of the problem in the Search Support (KB) field.

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