XWEB: Cannot View Attachments in OWA on IIS 4.0 Computer

• Microsoft Outlook Web Access, version 5.5
• Microsoft Internet Information Server version 4.0

SYMPTOMS

If you use Microsoft Outlook Web Access to view a message that contains an attachment on a Microsoft Exchange Server computer that is running Microsoft Internet Information Server (IIS) 4.0, you may be unable to open the attachment. Microsoft Internet Explorer is able to display the contents of the attachment, but other Internet browsers may not be able to do so.

CAUSE

When you view a message that contains an attachment, Outlook Web Access uses the IIS Multipurpose Internet Mail Extensions (MIME) table to determine which MIME type is associated with the file's extension. This allows your Internet browser to display the contents of the attachment.

In IIS 3.0, the MIME table is located in the registry. The MIME table is also located in the registry in IIS 4.0, but it is located under a different registry key. This prevents Outlook Web Access from determining which MIME type is associated with a given extension. Because it cannot obtain the correct MIME type, Outlook Web Access assumes that the MIME type is "application/octet-stream." Some Internet browsers can display the contents of the attachment under these circumstances, but others cannot.

WORKAROUND

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

• Save the attachment to your hard disk, and then open the file from your hard disk.



• If the file type associated with the attachment exists, modify the file type so that the appropriate MIME type is associated with it. To do so, follow these steps:
  
  
  1. In My Computer or Windows NT Explorer, click Folder Options on the View menu, and then click the File Types tab.
  
  
  
  2. Click the appropriate file type in the list of registered file types, and then click Edit.
  
  
  
  3. Verify that the appropriate MIME type is selected in the Content Type (MIME) box, click OK, and then click OK again.
  
  
  



• If the file type associated with the attachment does not exist, create it. To do so, follow these steps:
  
  
  1. In My Computer or Windows NT Explorer, click Folder Options on the View menu, and then click the File Types tab.
  
  
  
  2. Click New Type.
  
  
  
  3. Type a description for the file type in the Description Of Type box, type the file's extension is the Associated Extension box, and then select the appropriate MIME type in the Content Type (MIME) box.
  
  
  
  4. Click New, type "open" (without quotation marks) in the Action box, type the full path and file name of the program used to open the file in the Application Used To Perform Action box, click OK, click OK again, and then click OK again. Note that you can click Browse to locate the program instead of typing the full path and file name manually.
  
  
  

MORE INFORMATION

In IIS 3.0, the MIME table is located under the following registry key:

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Inetinfo
   \Parameters\MIMEMap 

   HKEY_CLASSES_ROOT\MIME\Database\Content Type 

STATUS

Microsoft has confirmed this to be a problem in Microsoft Outlook Web Access version 5.5. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.5. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: owa iis k2

Keywords          : XCLN XWEB 
Version           : WINDOWS:5.5; WINNT:4.0
Platform          : WINDOWS winnt 
Issue type        : kbbug