Hello,
qt5-styleplugins 5.0.0.20170311-17 upgrade (from qt5-styleplugins 5.0.0.20170311-16) broke keepassxc, due to a new version of Qt library.
command line output:
% keepassxc
(keepassxc:18371): Gtk-WARNING **: 15:34:20.987: Unable to locate theme engine in module_path: "adwaita",
(keepassxc:18371): Gtk-WARNING **: 15:34:20.987: Unable to locate theme engine in module_path: "adwaita",
(keepassxc:18371): Gtk-WARNING **: 15:34:20.990: Unable to locate theme engine in module_path: "adwaita",
(keepassxc:18371): Gtk-WARNING **: 15:34:20.990: Unable to locate theme engine in module_path: "adwaita",
QApplication: invalid style override passed, ignoring it.
Available styles: bb10dark, bb10bright, kvantum-dark, kvantum, cleanlooks, gtk2, cde, motif, plastique, qt5ct-style, Oxygen, Windows, Fusion
Cannot mix incompatible Qt library (version 0x50d02) with this library (version 0x50d01)
Aborted
anomalos:[fasma]:~/.config%
anomalos:[fasma]:/var/cache/pacman/pkg% pacman --help
usage: pacman <operation> [...]
Fortunately I had previous version in /var/cache/pacman/pkg, and downgraded via pacman -U. Maybe the packager of keepassxc could provide us with a package compiled with the new library, or the Qt-styleplugins might be downgraded to previous version for the time being.