diff --git a/sddmauthhelper.cpp b/sddmauthhelper.cpp
--- a/sddmauthhelper.cpp
+++ b/sddmauthhelper.cpp
@@ -67,6 +67,14 @@
 
 ActionReply SddmAuthHelper::sync(const QVariantMap &args)
 {
+    // initial check for sddm user; abort if user not present
+    // we have to check with QString and isEmpty() instead of QDir and exists() because
+    // QDir returns "." and true for exists() in the case of a non-existent user;
+    QString sddmHomeDirPath = KUser("sddm").homeDir();
+    if (sddmHomeDirPath.isEmpty()) {
+        return ActionReply::HelperErrorReply();
+    }
+
     // create SDDM config directory if it does not exist
     QDir sddmConfigLocation(args[QStringLiteral("sddmUserConfig")].toString());
     if (!sddmConfigLocation.exists()) {
@@ -151,6 +159,14 @@
 
 ActionReply SddmAuthHelper::reset(const QVariantMap &args)
 {
+    // initial check for sddm user; abort if user not present
+    // we have to check with QString and isEmpty() instead of QDir and exists() because
+    // QDir returns "." and true for exists() in the case of a non-existent user;
+    QString sddmHomeDirPath = KUser("sddm").homeDir();
+    if (sddmHomeDirPath.isEmpty()) {
+        return ActionReply::HelperErrorReply();
+    }
+
     QDir sddmConfigLocation(args[QStringLiteral("sddmUserConfig")].toString());
     QDir fontconfigDir(args[QStringLiteral("sddmUserConfig")].toString() + QStringLiteral("/fontconfig"));
 
diff --git a/src/advanceconfig.cpp b/src/advanceconfig.cpp
--- a/src/advanceconfig.cpp
+++ b/src/advanceconfig.cpp
@@ -147,6 +147,15 @@
 
 void AdvanceConfig::syncSettingsChanged()
 {
+    // initial check for sddm user; abort if user not present
+    // we have to check with QString and isEmpty() instead of QDir and exists() because
+    // QDir returns "." and true for exists() in the case of a non-existent user;
+    QString sddmHomeDirPath = KUser("sddm").homeDir();
+    if (sddmHomeDirPath.isEmpty()) {
+        KMessageBox::error(this, QStringLiteral("Cannot proceed, user 'sddm' does not exist. Please check your SDDM install."));
+        return;
+    }
+
     // read Plasma values
     KConfig cursorConfig(QStringLiteral("kcminputrc"));
     KConfigGroup cursorConfigGroup(&cursorConfig, "Mouse");
@@ -162,10 +171,10 @@
     QString numLock = numLockConfigGroup.readEntry("NumLock");
 
     // define paths
+    const QString sddmUserConfigPath = sddmHomeDirPath + QStringLiteral("/.config");
     const QString fontconfigPath = QStandardPaths::locate(QStandardPaths::GenericConfigLocation, QStringLiteral("fontconfig"), QStandardPaths::LocateDirectory);
     const QString kdeglobalsPath = QStandardPaths::locate(QStandardPaths::GenericConfigLocation, QStringLiteral("kdeglobals"));
     const QString plasmarcPath = QStandardPaths::locate(QStandardPaths::GenericConfigLocation, QStringLiteral("plasmarc"));
-    const QString sddmUserConfigPath = KUser("sddm").homeDir() + QStringLiteral("/.config");
 
     // send values and paths to helper, debug if it fails
     QVariantMap args;
@@ -251,8 +260,17 @@
 
 void AdvanceConfig::resetSettingsChanged()
 {
+    // initial check for sddm user; abort if user not present
+    // we have to check with QString and isEmpty() instead of QDir and exists() because
+    // QDir returns "." and true for exists() in the case of a non-existent user
+    QString sddmHomeDirPath = KUser("sddm").homeDir();
+    if (sddmHomeDirPath.isEmpty()) {
+        KMessageBox::error(this, QStringLiteral("Cannot proceed, user 'sddm' does not exist. Please check your SDDM install."));
+        return;
+    }
+
     // define paths
-    const QString sddmUserConfigPath = KUser("sddm").homeDir() + QStringLiteral("/.config");
+    const QString sddmUserConfigPath = sddmHomeDirPath + QStringLiteral("/.config");
 
     // send paths to helper
     QVariantMap args;