diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index 374dca82c2..56d19a0cb4 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -358,8 +358,6 @@ private:
 	/** Fill _presets with our presets */
 	virtual void find_presets () = 0;
 
-	void update_presets (std::string src_unique_id, Plugin* src );
-
 	/** Add state to an existing XMLNode */
 	virtual void add_state (XMLNode *) const = 0;
 
diff --git a/libs/ardour/luaproc.cc b/libs/ardour/luaproc.cc
index 436f60bfc4..4bc2c00c8b 100644
--- a/libs/ardour/luaproc.cc
+++ b/libs/ardour/luaproc.cc
@@ -1141,6 +1141,9 @@ LuaProc::do_save_preset (std::string name) {
 		return "";
 	}
 
+	// prevent dups -- just in case
+	t->root()->remove_nodes_and_delete (X_("label"), name);
+
 	std::string uri (preset_name_to_uri (name));
 
 	XMLNode* p = new XMLNode (X_("Preset"));
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index d21ecfe632..35495488dd 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -102,7 +102,6 @@ Plugin::Plugin (AudioEngine& e, Session& s)
 	, _parameter_changed_since_last_preset (false)
 {
 	_pending_stop_events.ensure_buffers (DataType::MIDI, 1, 4096);
-	PresetsChanged.connect_same_thread (_preset_connection, boost::bind (&Plugin::update_presets, this, _1 ,_2));
 }
 
 Plugin::Plugin (const Plugin& other)
@@ -117,7 +116,6 @@ Plugin::Plugin (const Plugin& other)
 	, _parameter_changed_since_last_preset (false)
 {
 	_pending_stop_events.ensure_buffers (DataType::MIDI, 1, 4096);
-	PresetsChanged.connect_same_thread (_preset_connection, boost::bind (&Plugin::update_presets, this, _1 ,_2));
 }
 
 Plugin::~Plugin ()
@@ -128,18 +126,23 @@ void
 Plugin::remove_preset (string name)
 {
 	Plugin::PresetRecord const * p = preset_by_label (name);
+	if (!p) {
+		PBD::error << _("Trying to remove nonexistent preset.") << endmsg;
+		return;
+	}
 	if (!p->user) {
 		PBD::error << _("Cannot remove plugin factory preset.") << endmsg;
 		return;
 	}
 
 	do_remove_preset (name);
-	_presets.erase (preset_by_label (name)->uri);
+	_presets.erase (p->uri);
 
 	_last_preset.uri = "";
 	_parameter_changed_since_last_preset = false;
-	PresetRemoved (); /* EMIT SIGNAL */
+	_have_presets = false;
 	PresetsChanged (unique_id(), this); /* EMIT SIGNAL */
+	PresetRemoved (); /* EMIT SIGNAL */
 }
 
 /** @return PresetRecord with empty URI on failure */
@@ -155,8 +158,9 @@ Plugin::save_preset (string name)
 
 	if (!uri.empty()) {
 		_presets.insert (make_pair (uri, PresetRecord (uri, name)));
-		PresetAdded (); /* EMIT SIGNAL */
+		_have_presets = false;
 		PresetsChanged (unique_id(), this); /* EMIT SIGNAL */
+		PresetAdded (); /* EMIT SIGNAL */
 	}
 
 	return PresetRecord (uri, name);
@@ -393,18 +397,6 @@ Plugin::resolve_midi ()
 	_have_pending_stop_events = true;
 }
 
-void
-Plugin::update_presets (std::string src_unique_id, Plugin* src )
-{
-	if (src == this || unique_id() != src_unique_id) {
-		return;
-	}
-	_have_presets = false;
-	// TODO check if a preset was added/removed and emit the proper signal
-	// so far no subscriber distinguishes between PresetAdded and PresetRemoved
-	PresetAdded();
-}
-
 vector<Plugin::PresetRecord>
 Plugin::get_presets ()
 {
diff --git a/libs/ardour/vst_plugin.cc b/libs/ardour/vst_plugin.cc
index a3dca8b3fa..9ebc80fd83 100644
--- a/libs/ardour/vst_plugin.cc
+++ b/libs/ardour/vst_plugin.cc
@@ -456,6 +456,8 @@ VSTPlugin::load_user_preset (PresetRecord r)
 	return false;
 }
 
+#include "sha1.c"
+
 string
 VSTPlugin::do_save_preset (string name)
 {
@@ -464,9 +466,23 @@ VSTPlugin::do_save_preset (string name)
 		return "";
 	}
 
+	// prevent dups -- just in case
+	t->root()->remove_nodes_and_delete (X_("label"), name);
+
 	XMLNode* p = 0;
-	/* XXX: use of _presets.size() + 1 for the unique ID here is dubious at best */
-	string const uri = string_compose (X_("VST:%1:%2"), unique_id (), _presets.size() + 1);
+
+	char tmp[32];
+	snprintf (tmp, 31, "%d", _presets.size() + 1);
+	tmp[31] = 0;
+
+	char hash[41];
+	Sha1Digest s;
+	sha1_init (&s);
+	sha1_write (&s, (const uint8_t *) name.c_str(), name.size ());
+	sha1_write (&s, (const uint8_t *) tmp, strlen(tmp));
+	sha1_result_hash (&s, hash);
+
+	string const uri = string_compose (X_("VST:%1:x%2"), unique_id (), hash);
 
 	if (_plugin->flags & 32 /* effFlagsProgramsChunks */) {