I have a vim file where every time I open it, it gives me a red message:
E823: Not an undo file: <filename>
Press ENTER of type command to continue
Doesn't appear to be an error, but it is very annoying. I've read about persisted undo files in newer versions of vim. But I don't know how it relates to this. So: - What is this trying to tell me? - How do I get rid of it?