I have been using Silk.app to customise the font I use on my System. However, I have since disabled it and have decided to revert back to the standard Mac font. Since doing this, certain parts of my system are using some horrible jagged font - which I have not seen before. Even if I re-apply Silk this font is still there on these portions of the UI. What can I do to remedy? Edit: Figured it out as I was pressing "post". It was the Font Smoothing!