diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
index ff37820401..1979e80374 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
@@ -41,7 +41,6 @@ void Foam::PstreamBuffers::finalExchange
     // Could also check that it is not called twice
     // but that is used for overlapping send/recv (eg, overset)
     finishedSendsCalled_ = true;
-    recvPositions_ = Zero;
 
     if (commsType_ == UPstream::commsTypes::nonBlocking)
     {
@@ -102,7 +101,6 @@ void Foam::PstreamBuffers::finalExchange
     // Could also check that it is not called twice
     // but that is used for overlapping send/recv (eg, overset)
     finishedSendsCalled_ = true;
-    recvPositions_ = Zero;
 
     if (commsType_ == UPstream::commsTypes::nonBlocking)
     {
@@ -140,7 +138,6 @@ void Foam::PstreamBuffers::finalExchangeGatherScatter
     // Could also check that it is not called twice
     // but that is used for overlapping send/recv (eg, overset)
     finishedSendsCalled_ = true;
-    recvPositions_ = Zero;
 
     if (commsType_ == UPstream::commsTypes::nonBlocking)
     {
diff --git a/src/Pstream/mpi/UPstream.C b/src/Pstream/mpi/UPstream.C
index 005707be61..61667ce2b0 100644
--- a/src/Pstream/mpi/UPstream.C
+++ b/src/Pstream/mpi/UPstream.C
@@ -535,12 +535,16 @@ void Foam::UPstream::allocatePstreamCommunicator
 
         PstreamGlobals::pendingMPIFree_[index] = PstreamGlobals::NonePending;
         PstreamGlobals::MPICommunicators_[index] = MPI_COMM_WORLD;
-        PstreamGlobals::MPIGroups_[index] = MPI_GROUP_NULL;
 
         // TBD: MPI_Comm_dup(MPI_COMM_WORLD, ...);
         // with pendingMPIFree_[index] = CommPending ...
         // Note: freePstreamCommunicator may need an update
 
+        MPI_Comm_group
+        (
+            PstreamGlobals::MPICommunicators_[index],
+           &PstreamGlobals::MPIGroups_[index]
+        );
         MPI_Comm_rank
         (
             PstreamGlobals::MPICommunicators_[index],
@@ -565,8 +569,8 @@ void Foam::UPstream::allocatePstreamCommunicator
 
         PstreamGlobals::pendingMPIFree_[index] = PstreamGlobals::NonePending;
         PstreamGlobals::MPICommunicators_[index] = MPI_COMM_SELF;
-        PstreamGlobals::MPIGroups_[index] = MPI_GROUP_NULL;
 
+        MPI_Comm_group(MPI_COMM_SELF, &PstreamGlobals::MPIGroups_[index]);
         MPI_Comm_rank(MPI_COMM_SELF, &myProcNo_[index]);
 
         // Number of ranks is always 1 (self communicator)
diff --git a/src/functionObjects/utilities/syncObjects/syncObjects.C b/src/functionObjects/utilities/syncObjects/syncObjects.C
index 88f613da6b..06776eae3b 100644
--- a/src/functionObjects/utilities/syncObjects/syncObjects.C
+++ b/src/functionObjects/utilities/syncObjects/syncObjects.C
@@ -90,9 +90,8 @@ void Foam::functionObjects::syncObjects::sync()
     // Note provision of explicit all-world communicator
     PstreamBuffers pBufs
     (
-        Pstream::commsTypes::nonBlocking,
-        UPstream::msgType(),
-        0
+        UPstream::globalComm,
+        UPstream::commsTypes::nonBlocking
     );