Vim Not an undo file

Question

I have a vim file where every time I open it, it gives me a red message:

E823: Not an undo file: <filename>

Followed by:

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?

Answer 1

Looks like there's a leftover undo file for the specific file you're editing, but it's empty.

Check for files ending in ~ in the file folder or, if you have persistent undo enable, in the undodir directory (should be in your .vimrc if configured).

If it's really empty, you can safely remove it to get rid of the error message.