You receive an error message when you try to play an .avi file in Windows Media Player

When you try to play an .avi file in Windows Media Player, you may receive any of the following error messages: This article is intended for a beginning to intermediate computer user.

When video files are created, they can be compressed to make the file size smaller by using a program (or compressor) that is installed on the developer's computer. When you play the video file, your computer must have a decompressor installed that can read that particular compression format. This program is called a codec.

When you try to play a file that uses a codec that is not installed on your computer, the Windows Media Player tries to download the codec from a Microsoft server. If the codec is available, the Windows Media Player installs it on your computer and then plays the file. However, if the codec is not available on the server (for example, because the codec was not created by Microsoft), the Windows Media Player displays a message that your computer is missing a codec.

In some cases, the file that you want to play uses a codec that is not available or compatible with the Windows Media Player. When that happens, you might be unable to use Windows Media Player to play this particular .avi file.

To resolve this problem, locate and download the required codec.

Before you start, you must know which version of Windows your computer is running. To determine which version of Windows that you are running. To verify that you are logged on to Windows with a user account that is a computer administrator, visit the following Microsoft Web site:Then, you must know your Windows Media Player version. If you are running Windows Vista, you are running Windows Media Player 11. If you are running Windows XP, check the help that is included with Windows Media Player to find the version.

After you determine which version of Windows Media Player you are running, go to the section for your operating system and Windows Media Player version.

Note If you are running a version of Windows Media Player that is earlier than 6.4, go to the "Earlier versions of Windows Media Player" bullet in the "Next steps" section for help.

If you use Windows Vista

In some cases, the error message in Windows Media Player will provide information about the codec file that is required. The error message might also provide a link that you can click to download the codec file. Therefore, to resolve the problem, play the .avi file and check the error message in Windows Media Player for help.

To resolve this problem, follow these steps.

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.
   
   Note If the link to the codec is not available, try searching the Internet for that particular codec to find where it is available. If you cannot determine which codec you must have or you cannot locate it, the codec might not be available. Or, it might not be compatible with the Windows Media Player. Therefore, you might be unable to use the Windows Media Player to play this particular.avi file.
4. After you download the appropriate codec file, replay the .avi file to see whether the problem is resolved.

If you still have problems playing the .avi file, go to the "Next steps" section to find other resources to help you with this problem.

If you use Windows XP with Windows Media Player 11, Windows Media Player 10, or Windows Media Player 9

In some cases, the error message in Windows Media Player will provide information about which codec file that is required. The error message might also provide a link that you can click to download the codec file. Therefore, to resolve the problem, play the .avi file and check the error message in Windows Media Player for help.

To resolve this problem, follow these steps.

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 click 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 the link to the codec is not available, try searching the Internet for that particular codec to find where it is available. If you cannot determine which codec you must have or you cannot locate it, the codec might not be available. Or, it might not be compatible with the Windows Media Player. Therefore, you might be unable to use the Windows Media Player to play this particular .avi file.
4. After you download the appropriate codec file, replay the .avi file to see whether the problem is resolved.

If you still have problems playing the .avi file, see the "Next steps" section to find other resources to help you with this problem.

If you use Windows XP with Windows Media Player 7.1, Windows Media Player 7, or Windows Media Player 6.4

In some cases, the error message includes the codec identifier, known as the FourCC identifier. You can use the FourCC identifier to find the manufacturer that created the codec. Then, see whether you can obtain the required codec from the manufacturer.

To resolve this problem, follow these steps.

1. Click Start, and then click Run. Copy and paste (or type) the following command in the Open box, and then press ENTER:
   mplay32.exe
2. On the File menu, click Open, 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, check for the FourCC identifier. If the FourCC identifier is available, note it. The four characters following the "vids:" or "vidc:" is the unique FourCC identifier that you can use to find the codec for this particular .avi file.
   
   For example, if the string is "vids:vcr2", "vcr2" is the FourCC identifier.
   
   Note If the FourCC identifier is not listed in the error message, unfortunately you cannot use Windows Media Player to play this particular .avi file.
4. Visit the following Web site, and then click Video codecs, located in the Content Overview section of the page:
   http://www.fourcc.org/ (http://www.fourcc.org/)
5. Use the FourCC identifier to find the manufacturer that created the codec. In step 3 for example, the FourCC identifier was "vcr2". Therefore, search for "vcr2" in the FOURCC column to find the codec and manufacturer. In this example, you will notice that "ATI Video Codec 2" is listed as the name of the codec and "ATI Technologies" is listed as the owner (or manufacturer).
   
   If you cannot find the codec or manufacturer listed, you might try searching for the codec and manufacturer on the Internet by using the FourCC identifier.
   
   Note Be aware that not all manufacturers provide their codecs for you to download. If you cannot obtain the required codec from the manufacturer, you will be unable to use the Windows Media Player to play this particular .avi file.
6. If a link to the manufacturer is provided on this Web site, use it to contact the manufacturer to obtain the required codec. If the link to the manufacturer is not available, try searching the Microsoft Knowledge Base for the manufacturer’s contact information.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:
   65416  (http://support.microsoft.com/kb/65416/ ) Hardware and software vendor contact information, A-K
   
   60781  (http://support.microsoft.com/kb/60781/ ) Hardware and software vendor contact information, L-P
   
   60782  (http://support.microsoft.com/kb/60782/ ) Hardware and software vendor contact information, Q-Z
   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. If the link to the manufacturer is not available on the Microsoft Knowledge Base Web site, try searching the Internet.
7. After you download the appropriate codec file, replay the .avi file to see whether the problem is resolved.

If you continue to have problems playing the .avi file, go to the "Next steps" section to find other resources to help you with this problem

If these methods did not work for you, you might want to ask someone you know for help. You can also visit the troubleshooting Web site for the Windows Media Player version that you are running. For more information about how to troubleshoot Windows Media Player, visit the following Microsoft Web sites:

• Windows Media Player 11 for Windows Vista
  http://www.microsoft.com/windows/windowsmedia/player/windowsvista/troubleshooting.aspx (http://www.microsoft.com/windows/windowsmedia/player/windowsvista/troubleshooting.aspx)
• Windows Media Player 11 for Windows XP
  http://www.microsoft.com/windows/windowsmedia/player/11/troubleshooting.aspx (http://www.microsoft.com/windows/windowsmedia/player/11/troubleshooting.aspx)
• Windows Media Player 10 and earlier versions of Windows Media Player
  http://www.microsoft.com/windows/windowsmedia/player/previousversions.aspx (http://www.microsoft.com/windows/windowsmedia/player/previousversions.aspx)

You can also use the Microsoft Customer Support Services Web site to find other solutions to your problem. Some services that the Microsoft Customer Support Services Web sites provide include the following:

• Searchable Knowledge Base (http://support.microsoft.com/search/?adv=1) : Search technical support information and self-help tools for Microsoft products.
• Solution Centers (http://support.microsoft.com/select/?target=hub) : View product-specific frequently asked questions and support highlights.
• Microsoft Customer Support Newsgroups (http://www.microsoft.com/communities/newsgroups/default.mspx) : Contact counterparts, peers, and Microsoft Most Valuable Professionals (MVPs).
• Other Support Options (http://support.microsoft.com/default.aspx?pr=csshome) : Use the Web to ask a question, contact Microsoft Customer Support Services, or provide feedback.

If you continue to have questions after you use these Microsoft Web sites or if you cannot find a solution on the Microsoft Support Services Web site, click the following link to contact Support:

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 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. For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base: