Cannot Open an Excel Attachment in Outlook Web Access

Exchange 2007

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Topic Last Modified: 2016-11-10

This topic provides information about how to work around an issue that may occur when you try to open a file attachment in Microsoft Office Outlook Web Access.

Assume that the following conditions are true:

  • You receive an e-mail message that contains an Office Excel 2007 file attachment.

  • You use double-byte character set encoding to name the file attachment. For example, the file name uses characters from the Korean, Japanese, or Chinese character set.

  • The file name is 13 characters or longer.

In this scenario, you experience the following symptoms:

  • When you try to open the attachment in Outlook Web Access, the file does not open.

  • When you save the file to the hard disk drive, the file is not saved with the original file name. Instead, the file is saved with a long string of characters. For example, the file is saved with a name that resembles the following:


This issue occurs when you use Windows Internet Explorer 7 or an earlier version of Internet Explorer to access Outlook Web Access. This issue occurs because of a limitation in Internet Explorer 7 and in earlier versions of Internet Explorer.

This issue does not occur when you use Internet Explorer 8 to access Outlook Web Access.

When you save or open an attachment that has a double-byte character set file name, Outlook Web Access converts the file name to 8-bit UCS/Unicode Transformation Format (UTF-8). This is to help prevent file name corruption.

If the UTF-8 encoded file name exceeds 76 characters for an Excel file, Internet Explorer truncates the beginning of the file name. Therefore, Internet Explorer cannot locate the file to open it.

Excel has a greater limitation on the file name length than other Office programs, such as Office Word 2007 or Office PowerPoint 2007. Therefore, in the scenario that is described in this topic, you may be able to open a Word attachment that has a double-byte character set name that exceeds 76 UTF-8 encoded characters. For example, Internet Explorer can open a Word attachment that has a double-byte character set name that, when encoded in UTF-8, is up to 152 characters.

To work around this issue, use one of the following methods:

  • Use Internet Explorer 8 to access Outlook Web Access. Internet Explorer 8 supports opening file names of up to 2,083 UTF-8 encoded characters.

  • Ask the sender to rename the Excel attachment using a shorter file name and then to resend it. For example, ask the sender to use a file name that is less than thirteen double-byte character set characters.

For more information about limitations for Office file names, see Microsoft Knowledge Base article 325573, You receive error messages when you try to open an Office document.

For more information about how to obtain Internet Explorer 8, see the Internet Explorer 8: Home page.