Microsoft KB Archive/841120

= Error message after you download a .ZIP file from a document library in Windows SharePoint Services: &quot;Cannot open file&quot; =

Article ID: 841120

Article Last Modified on 5/15/2007

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APPLIES TO


 * Microsoft Windows SharePoint Services 3.0
 * Microsoft Windows SharePoint Services 2.0
 * Microsoft Windows SharePoint Services
 * Microsoft Office SharePoint Server 2007
 * Microsoft Office SharePoint Portal Server 2003

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SYMPTOMS
After you download a .ZIP file from a Microsoft Windows SharePoint Services document library, and then you try to open the .ZIP file, you may receive the following error message:

Cannot open file: it does not appear to be a valid archive. If you downloaded this file, try downloading the file again.



CAUSE
This problem may occur if HTTP compression is turned on in the Web Sites properties of Microsoft Internet Information Services (IIS) on the SharePoint virtual server. When you download a .ZIP file, IIS encodes the file as GZIP. However, the browser client passes the file directly to the unZIP program, without GZIP decoding the file.

To determine if HTTP compression is turned on, follow these steps:
 * 1) Click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
 * 2) Expand the   tree, where   is the name of your IIS server.
 * 3) Right-click Web Sites, and then click Properties.
 * 4) Click the Service tab to view the HTTP compression properties.



WORKAROUND
To work around this problem, change the MIME type for the .ZIP file from application/x-zip-compressed to application/octet-stream. To change the MIME type, follow these steps:
 * 1) Click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
 * 2) Right-click the   tree, where   is the name of your IIS server, and then click Properties.
 * 3) Click MIME Types.
 * 4) Scroll down the registered MIME type list to find the .zip entry.
 * 5) Click the .zip application/x-zip-compressed entry, and then click Edit.
 * 6) Change the MIME type value to application/octet-stream.
 * 7) Stop and then restart the IIS Admin Service to apply the change to the MIME type.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

Additional query words: WSS archive sps portal WSSv3 WSSv2 MOSS2007 SPS2003

Keywords: kbopenfile kbtshoot kbprb kbhttp kbwebservices kbwebserver kbclientserver kbclient kberrmsg kbinterop kbnofix KB841120

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