diff --git a/sfizz/FilePool.cpp b/sfizz/FilePool.cpp
index e10377f3..9acec5e7 100644
--- a/sfizz/FilePool.cpp
+++ b/sfizz/FilePool.cpp
@@ -145,16 +145,17 @@ void sfz::FilePool::loadingThread() noexcept
 void sfz::FilePool::garbageThread() noexcept
 {
     while (!quitThread) {
+        fileHandleMutex.lock();
         for (auto handle = fileHandles.begin(); handle < fileHandles.end();) {
             if (handle->use_count() == 1) {
                 handle->reset();
-                std::lock_guard<std::mutex> guard { fileHandleMutex };
                 std::iter_swap(handle, fileHandles.end() - 1);
                 fileHandles.pop_back();
             } else {
                 handle++;
             }
         }
+        fileHandleMutex.unlock();
         std::this_thread::sleep_for(200ms);
     }
 }
diff --git a/sfizz/FilePool.h b/sfizz/FilePool.h
index 5c0c41db..eee11e7a 100644
--- a/sfizz/FilePool.h
+++ b/sfizz/FilePool.h
@@ -72,11 +72,11 @@ private:
     void loadingThread() noexcept;
     void garbageThread() noexcept;
     bool quitThread { false };
+    std::mutex fileHandleMutex;
+    std::vector<std::shared_ptr<AudioBuffer<float>>> fileHandles;
+    absl::flat_hash_map<absl::string_view, std::shared_ptr<AudioBuffer<float>>> preloadedData;
     std::thread fileLoadingThread { &FilePool::loadingThread, this };
     std::thread garbageCollectionThread { &FilePool::garbageThread, this };
-    std::vector<std::shared_ptr<AudioBuffer<float>>> fileHandles;
-    std::mutex fileHandleMutex;
-    absl::flat_hash_map<absl::string_view, std::shared_ptr<AudioBuffer<float>>> preloadedData;
     LEAK_DETECTOR(FilePool);
 };
 }
diff --git a/sfizz/Synth.cpp b/sfizz/Synth.cpp
index a2e61aba..cc3c2b04 100644
--- a/sfizz/Synth.cpp
+++ b/sfizz/Synth.cpp
@@ -108,6 +108,14 @@ void sfz::Synth::buildRegion(const std::vector<Opcode>& regionOpcodes)
 
 void sfz::Synth::clear()
 {
+    for (auto &voice: voices)
+        voice->reset();
+    for (auto& list: noteActivationLists)
+        list.clear();
+    for (auto& list: ccActivationLists)
+        list.clear();
+    regions.clear();
+    filePool.clear();
     hasGlobal = false;
     hasControl = false;
     numGroups = 0;
@@ -121,8 +129,6 @@ void sfz::Synth::clear()
     globalOpcodes.clear();
     masterOpcodes.clear();
     groupOpcodes.clear();
-    regions.clear();
-    filePool.clear();
 }
 
 void sfz::Synth::handleGlobalOpcodes(const std::vector<Opcode>& members)