diff --git a/kcms/krdb/krdb.cpp b/kcms/krdb/krdb.cpp
--- a/kcms/krdb/krdb.cpp
+++ b/kcms/krdb/krdb.cpp
@@ -136,11 +136,16 @@
   // export kwin's colors to qtrc for kstyle to use
   KConfigGroup wmCfgGroup(kglobalcfg, "WM");
 
+  // Only look up the default depth if there is a screen available
+  unsigned int pixmapDepth = 0;
+  if (QApplication::primaryScreen() != nullptr)
+    pixmapDepth = QPixmap::defaultDepth();
+
   // active colors
   QColor clr = newPal.color( QPalette::Active, QPalette::Background );
   clr = wmCfgGroup.readEntry("activeBackground", clr);
   settings.setValue(QStringLiteral("/qt/KWinPalette/activeBackground"), clr.name());
-  if (QPixmap::defaultDepth() > 8)
+  if (pixmapDepth > 8)
     clr = clr.dark(110);
   clr = wmCfgGroup.readEntry("activeBlend", clr);
   settings.setValue(QStringLiteral("/qt/KWinPalette/activeBlend"), clr.name());
@@ -157,7 +162,7 @@
   clr = newPal.color(QPalette::Inactive, QPalette::Background);
   clr = wmCfgGroup.readEntry("inactiveBackground", clr);
   settings.setValue(QStringLiteral("/qt/KWinPalette/inactiveBackground"), clr.name());
-  if (QPixmap::defaultDepth() > 8)
+  if (pixmapDepth > 8)
     clr = clr.dark(110);
   clr = wmCfgGroup.readEntry("inactiveBlend", clr);
   settings.setValue(QStringLiteral("/qt/KWinPalette/inactiveBlend"), clr.name());
diff --git a/kcms/lookandfeel/lnftool.cpp b/kcms/lookandfeel/lnftool.cpp
--- a/kcms/lookandfeel/lnftool.cpp
+++ b/kcms/lookandfeel/lnftool.cpp
@@ -34,7 +34,7 @@
 
 int main(int argc, char **argv)
 {
-    QApplication app(argc, argv);
+    QCoreApplication app(argc, argv);
 
     const QString description = i18n("Look and feel tool");
     const char version[] = "1.0";