Error "Could Not Open File" if text editor can not encode some character.
If there is some binary character that text editor can not decode, you get a constant "Could Not Open File" Error that can not even be hidden.
(gnome-text-editor:2): editor-document-WARNING **: 09:35:30.972: Failed to load file: There was a character encoding conversion error and it was needed to use a fallback character.
(gnome-text-editor:2): editor-session-WARNING **: 09:35:30.972: Failed to load document: There was a character encoding conversion error and it was needed to use a fallback character.
The error is a bit misleading too, I would not expect a simple encoding issue.