I have a website running iis7, on a windows 2008, 64 bit server. When we try to open a docx filetype, we first receive an error that the file cannot be opened because there are problems with the contents. When you click on more details it says the file is corrupted. When you tell it to open anyway, the file looks fine.
I have within IIS a mime type for docx. I have set this at application/vnd.ms-word.document.12 (which was default in IIS) and changed it to application/vnd.openxmlformats-officedocument.wordprocessingml.document which I found on the Microsoft site. Neither setting allowed the document to open without the error message.
I do not have a handler mapping or anything for this file type, just the mime type.
Any ideas would be appreciated.