On SpaceCachyOS (KDE/Wayland, NVIDIA RTX 4060, driver 615.78.08), Spectacle 6.8.0 segfaulted on every launch (SIGSEGV) with the crash thread QSGRenderThread inside libnvidia-eglcore via QRhi::endFrame — Qt’s QML window rendering through the EGL/GL path. It looked like “won’t open” but it was crashing in ~1s. Fix: force QtQuick software rendering for Spectacle only via systemd user drop-in ~/.config/systemd/user/app-org.kde.spectacle.service.d/override.conf with Environment=QT_QUICK_BACKEND=software (because the .desktop is DBusActivatable, all menu/hotkey launches go through that unit). Also aliased spectacle in ~/.bashrc for CLI. Force X11 (QT_QPA_PLATFORM=xcb) also works but is heavier. Real long-term fix = Qt or NVIDIA driver update.