diff --git a/src/libprojectM/MilkdropPreset/EvalLibMutex.cpp b/src/libprojectM/MilkdropPreset/EvalLibMutex.cpp
index 4de96098eb..4e5574e4e2 100644
--- a/src/libprojectM/MilkdropPreset/EvalLibMutex.cpp
+++ b/src/libprojectM/MilkdropPreset/EvalLibMutex.cpp
@@ -1,4 +1,15 @@
 #include <projectm-eval.h>
 
-void projectm_eval_memory_host_lock_mutex() {}
-void projectm_eval_memory_host_unlock_mutex() {}
+#include <mutex>
+
+static std::mutex s_evalMutex;
+
+void projectm_eval_memory_host_lock_mutex()
+{
+    s_evalMutex.lock();
+}
+
+void projectm_eval_memory_host_unlock_mutex()
+{
+    s_evalMutex.unlock();
+}