If you mean IE9 display XML files as text, you should Check to see if your XML DOM Document add-on has been disabled. You can check this by:
· Click Tools (the gear icon on the right side of the toolbar)
· Click Manage add-ons
· Under Show:, click All add-ons
· Click XML DOM Document
· Click Enable
· Click Close
· Close Internet Explorer (all windows)
· Open Internet Explorer
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