Curious .doc files

A couple of times recently, I've had Word .doc files sent to me, which Word refused to open: nor could Notepad or Wordpad open the files, but, IBM's Lotus Symphony (beta version) managed to open them without difficulty. Why it does so beats me, since Symphony uses the Open Document Format, but it's useful to know that it works. Once it is in Symphony, you can save as a Word .doc file and Word then copes with it happily.