How Can I Recover a Corrupt Document or Template – and Why Did It Become Corrupt?

Saving when resources are low can cause corruptions. If you notice Word start to slow down noticeably it's always best to quit and restart Word immediately; to close any other applications that are open; and to clear the clipboard, by selecting any character and copying it.

Rado, Dave and John McGhie. Word MVP Site, The (2005). Articles>Word Processing>Software>Microsoft Word