When a file is opened in MP4 Splitter it is being locked mutually exclusive so that changes to the same from other sources can not overwrite it. Would it be fine if the developers relax this restriction and add a feature that if a file is modified externally when it is open in the tool, the same could be offered to be reloaded. During the melee, the tool could have a temporary copy of the file for its internal processing. I hope this would be more friendly. I recently had a slight problem with this...