diff --git a/source/backend/engine/CarlaEngineJuce.cpp b/source/backend/engine/CarlaEngineJuce.cpp
index bfeb4a8d3..6cf07d7fe 100644
--- a/source/backend/engine/CarlaEngineJuce.cpp
+++ b/source/backend/engine/CarlaEngineJuce.cpp
@@ -106,6 +106,12 @@ public:
         CARLA_SAFE_ASSERT_RETURN(clientName != nullptr && clientName[0] != '\0', false);
         carla_debug("CarlaEngineJuce::init(\"%s\")", clientName);
 
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_PATCHBAY)
+        {
+            setLastError("Patchbay process mode is not implemented yet for non-JACK drivers, sorry!");
+            return false;
+        }
+
         if (pData->options.processMode != ENGINE_PROCESS_MODE_CONTINUOUS_RACK && pData->options.processMode != ENGINE_PROCESS_MODE_PATCHBAY)
         {
             setLastError("Invalid process mode");
diff --git a/source/backend/engine/CarlaEngineRtAudio.cpp b/source/backend/engine/CarlaEngineRtAudio.cpp
index 7a841443a..042321985 100644
--- a/source/backend/engine/CarlaEngineRtAudio.cpp
+++ b/source/backend/engine/CarlaEngineRtAudio.cpp
@@ -199,6 +199,12 @@ public:
         CARLA_SAFE_ASSERT_RETURN(clientName != nullptr && clientName[0] != '\0', false);
         carla_debug("CarlaEngineRtAudio::init(\"%s\")", clientName);
 
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_PATCHBAY)
+        {
+            setLastError("Patchbay process mode is not implemented yet for non-JACK drivers, sorry!");
+            return false;
+        }
+
         if (pData->options.processMode != ENGINE_PROCESS_MODE_CONTINUOUS_RACK && pData->options.processMode != ENGINE_PROCESS_MODE_PATCHBAY)
         {
             setLastError("Invalid process mode");