diff --git a/src/MPIIO/dump_atom_mpiio.cpp b/src/MPIIO/dump_atom_mpiio.cpp
index 2767847a6a..d4a2f29f8a 100644
--- a/src/MPIIO/dump_atom_mpiio.cpp
+++ b/src/MPIIO/dump_atom_mpiio.cpp
@@ -98,7 +98,7 @@ void DumpAtomMPIIO::openfile()
   }
   else { // replace open
 
-    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE | MPI_MODE_APPEND | MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
+    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE | MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
     if (err != MPI_SUCCESS) {
       char str[128];
       sprintf(str,"Cannot open dump file %s",filecurrent);
diff --git a/src/MPIIO/dump_custom_mpiio.cpp b/src/MPIIO/dump_custom_mpiio.cpp
index 2922ad30c0..7aac8e665a 100644
--- a/src/MPIIO/dump_custom_mpiio.cpp
+++ b/src/MPIIO/dump_custom_mpiio.cpp
@@ -119,7 +119,7 @@ void DumpCustomMPIIO::openfile()
   }
   else { // replace open
 
-    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE | MPI_MODE_APPEND | MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
+    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE | MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
     if (err != MPI_SUCCESS) {
       char str[128];
       sprintf(str,"Cannot open dump file %s",filecurrent);
diff --git a/src/MPIIO/dump_xyz_mpiio.cpp b/src/MPIIO/dump_xyz_mpiio.cpp
index 108ab8dfee..af1f96c94a 100644
--- a/src/MPIIO/dump_xyz_mpiio.cpp
+++ b/src/MPIIO/dump_xyz_mpiio.cpp
@@ -118,7 +118,7 @@ void DumpXYZMPIIO::openfile()
   }
   else { // replace open
 
-    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE | MPI_MODE_APPEND | MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
+    int err = MPI_File_open( world, filecurrent, MPI_MODE_CREATE |  MPI_MODE_WRONLY  , MPI_INFO_NULL, &mpifh);
     if (err != MPI_SUCCESS) {
       char str[128];
       sprintf(str,"Cannot open dump file %s",filecurrent);
diff --git a/src/MPIIO/restart_mpiio.cpp b/src/MPIIO/restart_mpiio.cpp
index 55935d09d3..c72e37f99e 100644
--- a/src/MPIIO/restart_mpiio.cpp
+++ b/src/MPIIO/restart_mpiio.cpp
@@ -58,7 +58,7 @@ void RestartMPIIO::openForRead(char *filename)
 
 void RestartMPIIO::openForWrite(char *filename)
 {
-  int err = MPI_File_open(world, filename, MPI_MODE_APPEND | MPI_MODE_WRONLY,
+  int err = MPI_File_open(world, filename, MPI_MODE_WRONLY,
                           MPI_INFO_NULL, &mpifh);
   if (err != MPI_SUCCESS) {
     char str[MPI_MAX_ERROR_STRING+128];