diff --git a/examples/mdi/sequence_driver.py b/examples/mdi/sequence_driver.py
index 66b9bc9aff..b04a1c23f2 100644
--- a/examples/mdi/sequence_driver.py
+++ b/examples/mdi/sequence_driver.py
@@ -137,9 +137,13 @@ def perform_tasks(world,mdicomm,dummy):
     if mode == "eval":
       pass
     elif mode == "run":
+      print("SENDING INIT_MD")
       mdi.MDI_Send_command("@INIT_MD",mdicomm)
+      print("SENDING NITERATE")
       mdi.MDI_Send_command(">NITERATE",mdicomm)
+      print("SENDING NITERATE data nsteps")
       mdi.MDI_Send(nsteps,1,mdi.MDI_INT,mdicomm)
+      print("SENDING DEFAULT")
       mdi.MDI_Send_command("@DEFAULT",mdicomm)
     elif mode == "min":
       mdi.MDI_Send_command("@INIT_OPTG",mdicomm)
diff --git a/src/MDI/library_mdi.cpp b/src/MDI/library_mdi.cpp
index 4048f805a5..112ce18d2d 100644
--- a/src/MDI/library_mdi.cpp
+++ b/src/MDI/library_mdi.cpp
@@ -131,6 +131,7 @@ The function executes a single command from an external MDI driver.
 
 int lammps_execute_mdi_command(const char *command, MDI_Comm comm, void *class_obj)
 {
+  printf("LIB wrapper command %s\n",command);
   MDIEngine *mdi_engine = (MDIEngine *) class_obj;
   return mdi_engine->execute_command(command,comm);
 }
diff --git a/src/MDI/mdi_engine.cpp b/src/MDI/mdi_engine.cpp
index 1244e72dc0..e9c5e4f8ec 100644
--- a/src/MDI/mdi_engine.cpp
+++ b/src/MDI/mdi_engine.cpp
@@ -186,12 +186,16 @@ void MDIEngine::mdi_engine(int narg, char **arg)
     // top-level mdi engine only recognizes three nodes
     // DEFAULT, INIT_MD, INIT_OPTG
 
+    printf("MAIN LOOP pre engine_node DEF\n");
     engine_node("@DEFAULT");
+    printf("MAIN LOOP post engine_node DEF\n");
 
     // MDI commands for dynamics or minimization
 
     if (strcmp(mdicmd,"@INIT_MD") == 0) {
+      printf("MAIN LOOP pre mdi_md\n");
       mdi_md();
+      printf("MAIN LOOP post mdi_md\n");
       if (exit_command) break;
 
     } else if (strcmp(mdicmd,"@INIT_OPTG") == 0) {
@@ -251,6 +255,8 @@ void MDIEngine::engine_node(const char *node)
     // read the next command from the driver
     // all procs call this, but only proc 0 receives the command
 
+    printf("PRE MDI RECV_command: node eng/drv: %s/%s\n",node_engine,node_driver);
+
     ierr = MDI_Recv_command(mdicmd,mdicomm);
     if (ierr) error->all(FLERR,"MDI: Unable to receive command from driver");
 
@@ -258,6 +264,8 @@ void MDIEngine::engine_node(const char *node)
 
     MPI_Bcast(mdicmd,MDI_COMMAND_LENGTH,MPI_CHAR,0,world);
 
+    printf("POST MDI RECV_command: node eng/drv: %s/%s\n",mdicmd);
+
     // execute the command
 
     execute_command(mdicmd,mdicomm);
@@ -306,6 +314,8 @@ int MDIEngine::execute_command(const char *command, MDI_Comm mdicomm)
   // receives first, sends second, node commands third
   // ---------------------------------------
 
+  printf("ABOUT to process command %s\n",command);
+
   if (strcmp(command,">CELL") == 0) {
     receive_cell();
 
@@ -607,7 +617,9 @@ void MDIEngine::mdi_md()
 
   niterate = -1;
 
+  printf("PRE @INIT_MD\n");
   engine_node("@INIT_MD");
+  printf("POST @INIT_MD %s\n",mdicmd);
   if (strcmp(mdicmd,"EXIT") == 0) return;
 
   // add an instance of fix MDI/ENGINE
diff --git a/src/library.cpp b/src/library.cpp
index a983b24b7f..ace9905451 100644
--- a/src/library.cpp
+++ b/src/library.cpp
@@ -172,9 +172,6 @@ void *lammps_open(int argc, char **argv, MPI_Comm comm, void **ptr)
   lammps_mpi_init();
   if (ptr) ptr_argument_warning();
 
-  printf("LAMMPS instantiate argc %d argv[1] %s argv[2] %s\n",
-         argc,argv[1],argv[2]);
-
 #ifdef LAMMPS_EXCEPTIONS
   try
   {
@@ -186,9 +183,7 @@ void *lammps_open(int argc, char **argv, MPI_Comm comm, void **ptr)
     if (ptr) *ptr = nullptr;
   }
 #else
-  printf("PRE-INSTANTIATE\n");
   lmp = new LAMMPS(argc, argv, comm);
-  printf("POST-INSTANTIATE %p\n",lmp);
   if (ptr) *ptr = (void *) lmp;
 #endif
   return (void *) lmp;