For a school project I need to collaborate with a lot of different people, and they all use MS Office. Of course they all have problems with opening .odt files. (even though MS says that Office should open them just fine..). They all get messages that the file is corrupt. Normally they can recover the content, but with messed up formatting.

So I was wondering.. what file format is the most compatible with Microsoft Word? Also another thing I wondered for a while.. I saw that there are two options for .docx when I save a new document, Office Open XML and Office 2007/2010 or something. Which of the 2 should I use?

Hopefully someone is able to help out! :)