diff --git a/examples/mdi/sequence_driver.py b/examples/mdi/sequence_driver.py
index ad1633ba2c..f658214759 100644
--- a/examples/mdi/sequence_driver.py
+++ b/examples/mdi/sequence_driver.py
@@ -290,22 +290,42 @@ if not mdiarg: error()
 # world = MPI communicator for just this driver
 # invoke perform_tasks() directly
 
-if not plugin:
-  mdi.MDI_Init(mdiarg)
-  world = mdi.MDI_MPI_get_world_comm()
+#if not plugin:
+#  mdi.MDI_Init(mdiarg)
+#  world = mdi.MDI_MPI_get_world_comm()
 
   # connect to engine
 
-  mdicomm = mdi.MDI_Accept_Communicator()
+#  mdicomm = mdi.MDI_Accept_Communicator()
 
-  perform_tasks(world,mdicomm,None)
+#  perform_tasks(world,mdicomm,None)
 
 # LAMMPS engine is a plugin library
 # launch plugin
 # MDI will call back to perform_tasks()
 
-if plugin:
-  mdi.MDI_Init(mdiarg)
+#if plugin:
+#  mdi.MDI_Init(mdiarg)
+#  world = MPI.COMM_WORLD
+#  plugin_args += " -mdi \"-role ENGINE -name lammps -method LINK\""
+#  mdi.MDI_Launch_plugin(plugin,plugin_args,world,perform_tasks,None)
+
+
+# new code to auto-detect whether engine is stand-alone code or plugin library
+
+mdi.MDI_Init(mdiarg)
+mdicomm = mdi.MDI_Get_communicator(0)
+
+if mdicomm == mdi.MDI_COMM_NULL:
+  world = mdi.MDI_MPI_get_world_comm()
+  mdicomm = mdi.MDI_Accept_Communicator()
+  if mdicomm == mdi.MDI_COMM_NULL:
+    error("MDI unable to connect to stand-alone engine")
+  perform_tasks(world,mdicomm,None)
+else:
   world = MPI.COMM_WORLD
+  method = mdi.MDI_Get_method(mdicomm)
+  if method != mdi.MDI_PLUGIN:
+    error("MDI internal error for plugin engine")
   plugin_args += " -mdi \"-role ENGINE -name lammps -method LINK\""
   mdi.MDI_Launch_plugin(plugin,plugin_args,world,perform_tasks,None)
diff --git a/src/MDI/fix_mdi_aimd.cpp b/src/MDI/fix_mdi_aimd.cpp
index f43b051020..055d7984b7 100644
--- a/src/MDI/fix_mdi_aimd.cpp
+++ b/src/MDI/fix_mdi_aimd.cpp
@@ -110,21 +110,24 @@ int FixMDIAimd::setmask()
 void FixMDIAimd::init()
 {
   if (mdicomm != MDI_COMM_NULL) return;
-
-  // one-time initialization of mdicomm
-  // plugin = 0/1 if MDI engine is a stand-alone code vs plugin library
+  
+  // one-time auto-detect whether engine is stand-alone code or plugin library
+  // also initializes mdicomm
+  // plugin = 0/1 for engine = stand-alone code vs plugin library
 
   MDI_Get_communicator(&mdicomm,0);
 
   if (mdicomm == MDI_COMM_NULL) { 
     plugin = 0;
     MDI_Accept_communicator(&mdicomm);
-    if (mdicomm <= 0) error->all(FLERR,"Unable to connect to MDI engine");
+    if (mdicomm == MDI_COMM_NULL) 
+      error->all(FLERR,"MDI unable to connect to stand-alone engine");
   } else {
     plugin = 1;
     int method;
     MDI_Get_method(&method,mdicomm);
-    if (method != MDI_PLUGIN) error->all(FLERR,"MDI internal error");
+    if (method != MDI_PLUGIN) 
+      error->all(FLERR,"MDI internal error for plugin engine");
   }
 }