Comment 8 for bug 1787989

Benji (benjim) wrote :

I agree, that the issue is about small "a" and capital "A". This fixes the problem for me:
>sudo ln -s /usr/share/icons/Adwaita /usr/share/icons/adwaita

Maybe, also this works (But as I'm not sure, if there are also programs, which look for Adwaita with a capital "A", I thought having a softlink would be the safest way):
sudo mv /usr/share/icons/Adwaita /usr/share/icons/adwaita