diff --git a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
index 7592986ed8..4418899db1 100644
--- a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
+++ b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
@@ -1329,7 +1329,7 @@ public:
 
     void refreshParameterList() override
     {
-        managedParameters.clear();
+        managedParameters.clear (false);
         paramIDToIndex.clear();
         AudioProcessorParameterGroup parameterGroups ({}, {}, {});
 
diff --git a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
index 3d439fed52..ecb0ccb7fd 100644
--- a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
+++ b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
@@ -180,7 +180,9 @@ public:
 
         inputs.clear();
         outputs.clear();
-        managedParameters.clear();
+        managedParameters.clear (false);
+        AudioProcessorParameterGroup group ({}, {}, {});
+        parameterTree.swapWith (group);
 
         for (unsigned int i = 0; i < plugin->PortCount; ++i)
         {