You receive an "Unable to download appropriate decompressor" error message in Windows Media Player

You may receive the following error message:

This problem may occur if one of the following conditions is true:

• The file was created by using Apple QuickTime version 3 or 4.
• You are trying to play a file format that is not supported by Microsoft Windows Media Player.
• You are trying to play a movie that contains audio and video that are both in unsupported formats, such as a file with a .mov file name extension that was originally created on an Apple Macintosh-based computer. The Apple Macintosh-based computer has video and audio codecs that are not supported by ActiveMovie or by Windows Media Player.
• Video compression is not installed.
• Microsoft Internet Explorer version 3.02 or later is not installed on your computer. To install decompressors, you must have Internet Explorer. Decompressors are used to play multimedia content. Although Internet Explorer must download decompressors, Internet Explorer does not have to be configured as the default browser.
• Your Internet security options are not set to permit decompressors to be downloaded.
• Installation of the decompressor requires a restart of your computer, but no restart occurred.
• The codec that you must have to play the file is missing or damaged.

To resolve this issue, follow these steps. After each step, test to determine if the issue is resolved.

Note Windows Media Player does not support playing every kind of media file that is currently available, but does provide support for the most common kinds of media files. Make sure that your media file is a supported kind. If your media file is not a supported kind, do not continue past step 1. If Windows Media Player does not support the file format that you are using, contact the distributor of the file to inquire about the availability of a viewer for the file.

1. Verify that Windows Media Player supports the file format that you are using. Windows Media Player supports the following file formats:
   • Windows Media formats: .asf, .asx, .avi, .wav, .wax, .wma, .wm, .wmv
   • Moving Pictures Experts Group (MPEG) formats: m3u, mp2v, .mpg, .mpeg, .m1v, .mp2, .mp3, .mpa, .mpe, mpv2
   • Musical Instrument Digital Interface (MIDI) formats: .mid, midi, .rmi
   • UNIX File formats: .au, .snd
   Note Windows Media Player does not support playing .avi files that are created by using the Microsoft MPEG4v3 codec. The file must be encoded again by using the original source in a supported format such as the .asf format. To do this, you can use the Windows Media tools. For additional information, visit the following Microsoft Web site:
   http://technet.microsoft.com/en-us/library/bb676148.aspx (http://technet.microsoft.com/en-us/library/bb676148.aspx)
   If you have access to the original source, contact the creator of the file and request that the creator convert the file to a supported Windows Media Player file type. Microsoft supports MPEG4v3 files in .asf streaming format only. These files are not supported in an .avi file format.
2. Verify that you can play a media file that uses the same file name extension as the file that you were playing when you received the error message. For example, try to play a file that uses the same file name extension from the Microsoft Windows 98 or Microsoft Windows Millennium Edition CD-ROM. For Microsoft Windows XP, search the drive for the Windows Movie Maker Sample.wmv file or for the files that are in the C:\Documents and Settings\All Users\Documents\My Music\Sample Music directory.
   
   For more information about file formats that Windows Media Player 7 and later support, click the following article number to view the article in the Microsoft Knowledge Base:
   316992  (http://support.microsoft.com/kb/316992/ ) Windows Media Player multimedia file formats
   If the other file plays correctly, the original file that you were trying to play may be damaged. If you receive an error message when you play both the files, go to the next step.
3. Install video compression. If video compression is not installed on your computer, video functionality may be limited. To install video compression, follow these steps.
   
   Windows 98-based and Windows 95-based computers:
   1. Click Start, point to Settings, click Control Panel, and then click Add/Remove Programs.
   2. On the Windows Setup tab, click Multimedia, and then click Details
   3. Click to select the Video Compression check box, click OK, and then click OK.
   Windows NT-based computers:
   • Obtain and install a third-party viewer.
   Windows XP-based computers:
   • Video compression is automatic.
4. Install the latest version of Internet Explorer. To do this, visit the following Microsoft Web site:
   http://www.microsoft.com/windows/ie/downloads/default.htm (http://www.microsoft.com/windows/ie/downloads/default.htm)
   Note Internet Explorer 6 is included with Windows XP. Do not try to reinstall Internet Explorer 6 in Windows XP.
5. Lower your Internet security to medium. To do this, follow these steps:
   1. Start Internet Explorer, and then click Internet Options on the Tools menu.
   2. On the Security tab, click Internet.
   3. Under Security Level For This Zone, click Default Level, and then move the slider to Medium.
   4. Click OK.
6. Restart your computer and then try to play the file again. If you still receive the error message, you may have to troubleshoot the codecs that are installed on the computer. For more information about verifying, installing, and troubleshooting audio codecs, see articles that are listed in the "More Information" section.
7. If you receive this error message when you try to play a file that was created with QuickTime 3 or 4, download the latest QuickTime player. To do this, visit the following Apple Web site:
   http://www.apple.com (http://www.apple.com)
8. If you receive this error message when you try to play a file that was created with RealPlayer, visit the following RealPlayer Web site:
   http://www.realplayer.com (http://www.realplayer.com)

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.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

For more information about verifying, installing, and troubleshooting audio codecs, click the following article numbers to view the articles in the Microsoft Knowledge Base: For more information about similar issues, click the following article number to view the article in the Microsoft Knowledge Base: