Hey, I'm not sure whether you still have the issue, but I had a similar one. The Error you have seen in the widgets extension log was a hint. When you use CTFontManagerRegisterFontsForURL you have to pass a CTFontManagerScope to define how long the dynamically loaded font should be available or alive. However, the option .user that you probably had chosen is not available in your widget extension target. So the font's are not loaded and the RegisterFonts function does return true, which is something I had not expected in this case. So you need to take a CTFontManagerScope value that is available within this context e.g. .process.