I have got this issue a couple of times when I change a font for another. After changing the font I erase all usage of the former font in styles and in "@font-face fonts" which I always use for my fonthandling. But when opening the project after this I get this error message:

I have tryed to save the project as a new project but the problem remains??
I ignore the error mesage and the webpage works ok, but if this can be fixed I'm greatful
