When you try to use Internet Explorer 7 to download a file from a Web page, the file name changes

You try to use Windows Internet Explorer 7 to download a file from a Web page. However, when you click the URL for the file, the file name changes.

This problem occurs if the following conditions are true:

• The Web page uses a content disposition header to force Windows Internet Explorer 7 to download a file instead of opening the file in a browser window.
• The file name in the content disposition header uses double-byte character set (DBCS) characters, such as Japanese characters.
• The second byte, or "trailbyte," of any of the DBCS characters contains values that represent file system-reserved characters in ASCII. For example, the "trailbyte" contains values that represent ASCII values such as 0x5c or 0x7c.

When this problem occurs, the "trailbyte" is changed to a different value. Therefore, the DBCS character is altered.

Note DBCS characters use two bytes of memory to display a single character. This character consists of a "leadbyte" and a "trailbyte." These two bytes together determine which character of the target language is displayed.

Security update information

To resolve this problem, install the most current cumulative security update for Internet Explorer. To install the most current updates, visit the following Microsoft Web site: For more technical information about the most current cumulative security update for Internet Explorer, visit the following Microsoft Web site: Note This fix was first included in security update 937143 (MS07-045). For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

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.

Internet Explorer 7 in Windows Vista

Internet Explorer 7 for Microsoft Windows XP with Service Pack 2

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