> Which is why I asked if you had upgraded that recently. Thank for your comments Allan
I noticed the problem in the very first boot with Qt 5.9.1, as soon as I opened Dolphin. I don't know if freetype was also upgraded or not at that moment. I remember an upgrade to libfreetype6 some weeks ago that also broke my font rendering. I solved it adding FREETYPE_PROPERTIES="truetype:interpreter-version=35" as commented in this bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=866685 It worked nice and fonts were rendered again as they should be but with Qt 5.9.1 I noticed those particular texts in Qt programs (which seems have bold property enabled) are rendered in a bad form. Everything else in Qt programs is rendered as expected. GTK programs are not affected at all.