FIX: Content-Disposition: Attachment Saves Wrong Filename for Unknown Extension

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View products that this article applies to.

This article was previously published under Q262042

SYMPTOMS

Developers can return a file from Internet Information Server with a "Content-disposition: attachment" header to force a "Save As" operation by Internet Explorer:

Content-disposition: attachment; filename=newName.zzz

If the filename contains an extension unknown to the client computer that is receiving the file (an extension not mapped to any MIME type) Internet Explorer prompts the user to save the file with a double extension. In this example, "newName.zzz" would be saved as "newName.zzz..zzz".

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RESOLUTION

There is no known resolution for Internet Explorer 5.0.

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

This bug was corrected in Internet Explorer 5.01.

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MORE INFORMATION

Steps to Reproduce Behavior

Save a text file on the root of your Web server and name it "File.txt".
Go into Internet Services Manager in Internet Information Server, right-click the document, and select Properties.
Go to the HTTP Headers tab and click Add. In the Custom Header Name box, type Content-disposition. In the Custom Header Value box, type attachment; filename=newName.zzz.
Use Internet Explore 5 to access the text file through your Web server. You will be prompted to save it to disk.
Examine the file on disk. It will be named "newName.zzz..zzz".

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REFERENCES

For more information about developing Web-based solutions for Microsoft Internet Explorer, visit the following Microsoft Web sites:

http://msdn.microsoft.com/ie/ (http://msdn.microsoft.com/ie/)

http://support.microsoft.com/iep (http://support.microsoft.com/iep)

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APPLIES TO

Microsoft Internet Explorer 5.0

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kbbug kbfix kbie501fix kbnavigation KB262042

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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