T. Stück

It can be difficult to locate a windows font used somewhere in an upgraded site (although I do hope Incomedia is looking to provide assistance in an upcoming update, I too have a font "somewhere" in a project and I cannot locate it)

There are 3 approaches you can take, the first is to ignore the warning message, and assuming your default font is a websafe font, it will replace your non-websafe font.

http://static.incomedia.eu/websitex5.com/pdf/EN/v13tov14EN.pdf?_ga=2.238585928.976287979.1503***8145216.1501141496

The second would be to get a copy of the missing segoe print.ttf, copy it to your hard drive and embed it as a webfont in your project. The ttf is in your windows/fonts directory (I believe you need to move it) or can be downloaded off the web eg https://www.wfonts.com/font/segoe-print but I am not sure of the legality of either of these moves.

The third (& best option) is to locate where this font is used and replace it. My recommendation is to use the google font option, there are many fonts that you may find suitable as a replacement https://fonts.google.com/?category=Handwriting

Adding fonts to a project is very simple https://helpcenter.websitex5.com/de/post/179411