How to get Internet Information Server to work with new Office 2010 / 2007 documents

This morning I got a call from an Administrative Assistant about a new Office 2010 document not working on our intranet web site. It was giving her the 404 File not Found Error. After confirming the URL of the file was correct, it dawned on me that IIS has locked down the MIME types. We recently upgraded our computers from Office 2000 to Office 2010, so that means new file extensions are in effect: docx, xlsx, pptx, etc.

Here's how to fix the problem in Internet Information Services 6.0 (IIS):
1. Open your IIS Manager.
2. Right click on Web Sites.
3. Choose Properties
4. Go to the HTTP Headers tab.
5. Click the "Mime Types..." button
6. Add the following MIME types:

.docm application/vnd.ms-word.document.macroEnabled.12
.docx application/vnd.openxmlformats-officedocument.wordprocessingml.document
.dotm application/vnd.ms-word.template.macroEnabled.12
.dotx application/vnd.openxmlformats-officedocument.wordprocessingml.template
.potm application/vnd.ms-powerpoint.template.macroEnabled.12
.potx application/vnd.openxmlformats-officedocument.presentationml.template
.ppam application/vnd.ms-powerpoint.addin.macroEnabled.12
.ppsm application/vnd.ms-powerpoint.slideshow.macroEnabled.12
.ppsx application/vnd.openxmlformats-officedocument.presentationml.slideshow
.pptm application/vnd.ms-powerpoint.presentation.macroEnabled.12
.pptx application/vnd.openxmlformats-officedocument.presentationml.presentation
.xlam application/vnd.ms-excel.addin.macroEnabled.12
.xlsb application/vnd.ms-excel.sheet.binary.macroEnabled.12
.xlsm application/vnd.ms-excel.sheet.macroEnabled.12
.xlsx application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.xltm application/vnd.ms-excel.template.macroEnabled.12
.xltx application/vnd.openxmlformats-officedocument.spreadsheetml.template

If you look behind the scenes, we are actually modifying the MimeMap attribute under the IIsWebService Location="/LM/W3SVC" in your MetaBase.xml file (C:\WINDOWS\system32\inetsrv\MetaBase.xml). If you're not comfortable with editing XML files, stick to steps 1-6 above and you'll be good-to-go.

Drop me a note to let me know if this solution helps you!