diff --git a/source/carla.py b/source/carla.py
index 0beb12343..8a1b01a64 100755
--- a/source/carla.py
+++ b/source/carla.py
@@ -773,6 +773,11 @@ class CarlaMainW(QMainWindow):
             self.scene.render(painter)
             self.fExportImage.save(newPath, imgFormat, 100)
 
+    def showLastError(self, isProject):
+        CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"),
+                         self.tr("Failed to load %s" % (self.tr("project") if isProject else self.tr("plugin"))),
+                         cString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
+
     @pyqtSlot(QModelIndex)
     def slot_fileTreeDoubleClicked(self, modelIndex):
         filename = self.fDirModel.filePath(modelIndex)
@@ -787,16 +792,20 @@ class CarlaMainW(QMainWindow):
         extension = filename.rsplit(".", 1)[-1].lower()
 
         if extension == "carxp":
-            Carla.host.load_project(filename)
+            if not Carla.host.load_project(filename):
+                self.showLastError(True)
 
         elif extension == "gig":
-            Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_GIG, filename, None, basename, None)
+            if not Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_GIG, filename, None, basename, None):
+                self.showLastError(False)
 
         elif extension == "sf2":
-            Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_SF2, filename, None, basename, None)
+            if not Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_SF2, filename, None, basename, None):
+                self.showLastError(False)
 
         elif extension == "sfz":
-            Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_SFZ, filename, None, basename, None)
+            if not Carla.host.add_plugin(BINARY_NATIVE, PLUGIN_SFZ, filename, None, basename, None):
+                self.showLastError(False)
 
         elif extension in ("aac", "flac", "oga", "ogg", "mp3", "wav"):
             self.fLastLoadedPluginId = -2
@@ -807,8 +816,7 @@ class CarlaMainW(QMainWindow):
                 Carla.host.set_custom_data(idx, CUSTOM_DATA_STRING, "file00", filename)
             else:
                 self.fLastLoadedPluginId = -1
-                CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"), self.tr("Failed to load plugin"),
-                                 cString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
+                self.showLastError(False)
 
         elif extension in ("mid", "midi"):
             self.fLastLoadedPluginId = -2
@@ -819,8 +827,7 @@ class CarlaMainW(QMainWindow):
                 Carla.host.set_custom_data(idx, CUSTOM_DATA_STRING, "file", filename)
             else:
                 self.fLastLoadedPluginId = -1
-                CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"), self.tr("Failed to load plugin"),
-                                 cString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
+                self.showLastError(False)
 
     @pyqtSlot(float)
     def slot_canvasScaleChanged(self, scale):
diff --git a/source/utils/CarlaStateUtils.hpp b/source/utils/CarlaStateUtils.hpp
index 31a15669f..b1d7949eb 100644
--- a/source/utils/CarlaStateUtils.hpp
+++ b/source/utils/CarlaStateUtils.hpp
@@ -51,6 +51,9 @@ struct StateParameter {
         if (symbol != nullptr)
             delete[] symbol;
     }
+
+    StateParameter(StateParameter&) = delete;
+    StateParameter(const StateParameter&) = delete;
 };
 
 struct StateCustomData {
@@ -72,6 +75,9 @@ struct StateCustomData {
         if (value != nullptr)
             delete[] value;
     }
+
+    StateCustomData(StateCustomData&) = delete;
+    StateCustomData(const StateCustomData&) = delete;
 };
 
 typedef QVector<StateParameter*> StateParameterVector;
@@ -190,6 +196,9 @@ struct SaveState {
         parameters.clear();
         customData.clear();
     }
+
+    SaveState(SaveState&) = delete;
+    SaveState(const SaveState&) = delete;
 };
 
 // -------------------------------------------------
@@ -307,7 +316,7 @@ const SaveState& getSaveStateDictFromXML(const QDomNode& xmlNode)
                 {
                     bool ok;
                     short value = text.toShort(&ok);
-                    if (ok && value < INT8_MAX)
+                    if (ok && value >= 1 && value < INT8_MAX)
                         saveState.ctrlChannel = static_cast<int8_t>(value-1);
                 }
 
@@ -318,7 +327,8 @@ const SaveState& getSaveStateDictFromXML(const QDomNode& xmlNode)
                 {
                     bool ok;
                     int value = text.toInt(&ok);
-                    if (ok) saveState.currentProgramIndex = value-1;
+                    if (ok && value >= 1)
+                        saveState.currentProgramIndex = value-1;
                 }
                 else if (tag.compare("CurrentProgramName", Qt::CaseInsensitive) == 0)
                 {
@@ -332,13 +342,15 @@ const SaveState& getSaveStateDictFromXML(const QDomNode& xmlNode)
                 {
                     bool ok;
                     int value = text.toInt(&ok);
-                    if (ok) saveState.currentMidiBank = value-1;
+                    if (ok && value >= 1)
+                        saveState.currentMidiBank = value-1;
                 }
                 else if (tag.compare("CurrentMidiProgram", Qt::CaseInsensitive) == 0)
                 {
                     bool ok;
                     int value = text.toInt(&ok);
-                    if (ok) saveState.currentMidiProgram = value-1;
+                    if (ok && value >= 1)
+                        saveState.currentMidiProgram = value-1;
                 }
 
                 // ----------------------------------------------
@@ -379,14 +391,14 @@ const SaveState& getSaveStateDictFromXML(const QDomNode& xmlNode)
                         {
                             bool ok;
                             ushort channel = pText.toUShort(&ok);
-                            if (ok && channel > 0 && channel < MAX_MIDI_CHANNELS)
+                            if (ok && channel >= 1 && channel < MAX_MIDI_CHANNELS)
                                 stateParameter->midiChannel = static_cast<uint8_t>(channel-1);
                         }
                         else if (pTag.compare("MidiCC", Qt::CaseInsensitive) == 0)
                         {
                             bool ok;
                             int cc = pText.toInt(&ok);
-                            if (ok && cc > 0 && cc < INT16_MAX)
+                            if (ok && cc >= 1 && cc < INT16_MAX)
                                 stateParameter->midiCC = static_cast<int16_t>(cc);
                         }