This has also happened to me without system crashes etc. That is the file edits that have been made have not been committed to disk. Currently I am trying to flush cache manually often to prevent this. Part of the issue might be that I am working with a slow media. Could the cache (or cache flushing) be made more aggressive (or disable it)? Or a setting to that effect? Currently I am left being unsure if my edits have been written down or not.