diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/IPstreams.C b/src/OpenFOAM/db/IOstreams/Pstreams/IPstreams.C
index d82a270238..340f0a2f99 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/IPstreams.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/IPstreams.C
@@ -77,7 +77,7 @@ Foam::UIPstream::UIPstream(const int fromProcNo, PstreamBuffers& buffers)
 
         if (debug)
         {
-            Pout<< "UIPstream::UIPstream PstreamBuffers :"
+            Perr<< "UIPstream::UIPstream PstreamBuffers :"
                 << " fromProcNo:" << fromProcNo_
                 << " tag:" << tag_ << " comm:" << comm_
                 << " receive buffer size:" << messageSize_
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineGather.C b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineGather.C
index ac47fdef69..4e37481e56 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineGather.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineGather.C
@@ -78,7 +78,7 @@ void Foam::Pstream::combineGather
 
                 if (debug & 2)
                 {
-                    Pout<< " received from "
+                    Perr<< " received from "
                         << belowID << " data:" << received << endl;
                 }
 
@@ -98,7 +98,7 @@ void Foam::Pstream::combineGather
 
                 if (debug & 2)
                 {
-                    Pout<< " received from "
+                    Perr<< " received from "
                         << belowID << " data:" << received << endl;
                 }
 
@@ -111,7 +111,7 @@ void Foam::Pstream::combineGather
         {
             if (debug & 2)
             {
-                Pout<< " sending to " << myComm.above()
+                Perr<< " sending to " << myComm.above()
                     << " data:" << value << endl;
             }
 
@@ -190,7 +190,7 @@ void Foam::Pstream::listCombineGather
 
                 if (debug & 2)
                 {
-                    Pout<< " received from "
+                    Perr<< " received from "
                         << belowID << " data:" << received << endl;
                 }
 
@@ -213,7 +213,7 @@ void Foam::Pstream::listCombineGather
 
                 if (debug & 2)
                 {
-                    Pout<< " received from "
+                    Perr<< " received from "
                         << belowID << " data:" << received << endl;
                 }
 
@@ -229,7 +229,7 @@ void Foam::Pstream::listCombineGather
         {
             if (debug & 2)
             {
-                Pout<< " sending to " << myComm.above()
+                Perr<< " sending to " << myComm.above()
                     << " data:" << values << endl;
             }
 
@@ -306,7 +306,7 @@ void Foam::Pstream::mapCombineGather
 
             if (debug & 2)
             {
-                Pout<< " received from "
+                Perr<< " received from "
                     << belowID << " data:" << received << endl;
             }
 
@@ -337,7 +337,7 @@ void Foam::Pstream::mapCombineGather
         {
             if (debug & 2)
             {
-                Pout<< " sending to " << myComm.above()
+                Perr<< " sending to " << myComm.above()
                     << " data:" << values << endl;
             }
 
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamGatherList.C b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamGatherList.C
index e3705feed5..5b3719e961 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamGatherList.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamGatherList.C
@@ -107,7 +107,7 @@ void Foam::Pstream::gatherList
 
                 if (debug & 2)
                 {
-                    Pout<< " received through "
+                    Perr<< " received through "
                         << belowID << " data from:" << belowID
                         << " data:" << values[belowID] << endl;
                 }
@@ -119,7 +119,7 @@ void Foam::Pstream::gatherList
 
                     if (debug & 2)
                     {
-                        Pout<< " received through "
+                        Perr<< " received through "
                             << belowID << " data from:" << leafID
                             << " data:" << values[leafID] << endl;
                     }
@@ -136,7 +136,7 @@ void Foam::Pstream::gatherList
 
             if (debug & 2)
             {
-                Pout<< " sending to " << myComm.above()
+                Perr<< " sending to " << myComm.above()
                     << " data from me:" << myProci
                     << " data:" << values[myProci] << endl;
             }
@@ -177,7 +177,7 @@ void Foam::Pstream::gatherList
                 {
                     if (debug & 2)
                     {
-                        Pout<< " sending to "
+                        Perr<< " sending to "
                             << myComm.above() << " data from:" << leafID
                             << " data:" << values[leafID] << endl;
                     }
@@ -259,7 +259,7 @@ void Foam::Pstream::scatterList
 
                     if (debug & 2)
                     {
-                        Pout<< " received through "
+                        Perr<< " received through "
                             << myComm.above() << " data for:" << leafID
                             << " data:" << values[leafID] << endl;
                     }
@@ -310,7 +310,7 @@ void Foam::Pstream::scatterList
 
                     if (debug & 2)
                     {
-                        Pout<< " sent through "
+                        Perr<< " sent through "
                             << belowID << " data for:" << leafID
                             << " data:" << values[leafID] << endl;
                     }
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
index aff75a17c0..8bd8b474cf 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H
@@ -61,8 +61,8 @@ void reduce
     {
         if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
         {
-            Pout<< "** reducing:" << value << " with comm:" << comm << endl;
-            error::printStack(Pout);
+            Perr<< "** reducing:" << value << " with comm:" << comm << endl;
+            error::printStack(Perr);
         }
         Pstream::gather(value, bop, tag, comm);
         Pstream::broadcast(value, comm);
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UIPstreamBase.C b/src/OpenFOAM/db/IOstreams/Pstreams/UIPstreamBase.C
index a8d2c9e532..cfbb324164 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UIPstreamBase.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UIPstreamBase.C
@@ -257,7 +257,7 @@ Foam::UIPstreamBase::~UIPstreamBase()
     {
         if (debug)
         {
-            Pout<< "UIPstreamBase Destructor : tag:" << tag_
+            Perr<< "UIPstreamBase Destructor : tag:" << tag_
                 << " fromProcNo:" << fromProcNo_
                 << " clearing receive buffer of size "
                 << recvBuf_.size()
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
index cf531d1014..c0dae071f9 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
@@ -221,7 +221,7 @@ void Foam::UPstream::setParRun(const label nProcs, const bool haveThreads)
 
     if (debug)
     {
-        Pout<< "UPstream::setParRun :"
+        Perr<< "UPstream::setParRun :"
             << " nProcs:" << nProcs
             << " haveThreads:" << haveThreads
             << endl;
@@ -274,7 +274,7 @@ Foam::label Foam::UPstream::allocateCommunicator
 
     if (debug)
     {
-        Pout<< "Allocating communicator " << index << nl
+        Perr<< "Allocating communicator " << index << nl
             << "    parent : " << parentIndex << nl
             << "    procs  : " << subRanks << nl
             << endl;
@@ -335,7 +335,7 @@ Foam::label Foam::UPstream::allocateCommunicator
 
     if (debug)
     {
-        Pout<< "Allocating communicator " << index << nl
+        Perr<< "Allocating communicator " << index << nl
             << "    parent : " << parentIndex << nl
             << "    procs  : " << flatOutput(subRanks) << nl
             << endl;
@@ -492,7 +492,7 @@ bool Foam::UPstream::allocateHostCommunicatorPairs()
 
     if (debug)
     {
-        Pout<< "Allocating host communicators "
+        Perr<< "Allocating host communicators "
             << interHostComm_ << ", " << intraHostComm_ << nl
             << "    parent : " << parentCommunicator << nl
             << endl;
@@ -588,7 +588,7 @@ void Foam::UPstream::freeCommunicator
 
     if (debug)
     {
-        Pout<< "Communicators : Freeing communicator " << communicator
+        Perr<< "Communicators : Freeing communicator " << communicator
             << " parent: " << parentComm_[communicator]
             << " myProcNo: " << myProcNo_[communicator]
             << endl;
diff --git a/src/OpenFOAM/db/error/messageStream.C b/src/OpenFOAM/db/error/messageStream.C
index 0953f53d75..2401debdf4 100644
--- a/src/OpenFOAM/db/error/messageStream.C
+++ b/src/OpenFOAM/db/error/messageStream.C
@@ -145,8 +145,8 @@ Foam::OSstream& Foam::messageStream::masterStream(const label communicator)
 {
     if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
-        Pout<< "** messageStream with comm:" << communicator << endl;
-        error::printStack(Pout);
+        Perr<< "** messageStream with comm:" << communicator << endl;
+        error::printStack(Perr);
     }
 
     if (communicator == UPstream::worldComm || UPstream::master(communicator))
diff --git a/src/Pstream/mpi/UIPBstreamRead.C b/src/Pstream/mpi/UIPBstreamRead.C
index 0ee1d63ce3..5080583396 100644
--- a/src/Pstream/mpi/UIPBstreamRead.C
+++ b/src/Pstream/mpi/UIPBstreamRead.C
@@ -60,7 +60,7 @@ void Foam::UIPBstream::bufferIPCrecv()
 
     if (UPstream::debug)
     {
-        Pout<< "UOPBstream IPC read buffer :"
+        Perr<< "UOPBstream IPC read buffer :"
             << " root:" << fromProcNo_
             << " comm:" << comm_
             << " probed size:" << label(bufSize)
diff --git a/src/Pstream/mpi/UIPstreamRead.C b/src/Pstream/mpi/UIPstreamRead.C
index 2a690f4b9f..bec4a2e87f 100644
--- a/src/Pstream/mpi/UIPstreamRead.C
+++ b/src/Pstream/mpi/UIPstreamRead.C
@@ -68,17 +68,17 @@ static std::streamsize UPstream_mpi_receive
 
     if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
-        Pout<< "UIPstream::read : starting read from:" << fromProcNo
+        Perr<< "UIPstream::read : starting read from:" << fromProcNo
             << " size:" << label(bufSize)
             << " tag:" << tag << " comm:" << communicator
             << " commsType:" << UPstream::commsTypeNames[commsType]
             << " warnComm:" << UPstream::warnComm
             << Foam::endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
     else if (UPstream::debug)
     {
-        Pout<< "UIPstream::read : starting read from:" << fromProcNo
+        Perr<< "UIPstream::read : starting read from:" << fromProcNo
             << " size:" << label(bufSize)
             << " tag:" << tag << " comm:" << communicator
             << " commsType:" << UPstream::commsTypeNames[commsType]
@@ -123,7 +123,7 @@ static std::streamsize UPstream_mpi_receive
         }
         else if (UPstream::debug)
         {
-            Pout<< "UIPstream::read : finished recv from:"
+            Perr<< "UIPstream::read : finished recv from:"
                 << fromProcNo
                 << " size:" << label(bufSize) << " tag:" << tag
                 << Foam::endl;
@@ -198,7 +198,7 @@ static std::streamsize UPstream_mpi_receive
 
         if (UPstream::debug)
         {
-            Pout<< "UIPstream::read : started non-blocking recv from:"
+            Perr<< "UIPstream::read : started non-blocking recv from:"
                 << fromProcNo
                 << " size:" << label(bufSize) << " tag:" << tag
                 << " request:" <<
@@ -225,7 +225,7 @@ void Foam::UIPstream::bufferIPCrecv()
     // Called by constructor
     if (UPstream::debug)
     {
-        Pout<< "UIPstream IPC read buffer :"
+        Perr<< "UIPstream IPC read buffer :"
             << " from:" << fromProcNo_
             << " tag:" << tag_ << " comm:" << comm_
             << " wanted size:" << recvBuf_.capacity()
@@ -291,7 +291,7 @@ void Foam::UIPstream::bufferIPCrecv()
 
         if (UPstream::debug)
         {
-            Pout<< "UIPstream::UIPstream : probed size:"
+            Perr<< "UIPstream::UIPstream : probed size:"
                 << label(count) << Foam::endl;
         }
 
diff --git a/src/Pstream/mpi/UOPstreamWrite.C b/src/Pstream/mpi/UOPstreamWrite.C
index 8613c17dfc..a8f4f04385 100644
--- a/src/Pstream/mpi/UOPstreamWrite.C
+++ b/src/Pstream/mpi/UOPstreamWrite.C
@@ -74,17 +74,17 @@ bool Foam::UOPstream::write
 
     if (UPstream::warnComm >= 0 && communicator != UPstream::warnComm)
     {
-        Pout<< "UOPstream::write : starting write to:" << toProcNo
+        Perr<< "UOPstream::write : starting write to:" << toProcNo
             << " size:" << label(bufSize)
             << " tag:" << tag << " comm:" << communicator
             << " commType:" << UPstream::commsTypeNames[commsType]
             << " warnComm:" << UPstream::warnComm
             << Foam::endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
     else if (UPstream::debug)
     {
-        Pout<< "UOPstream::write : starting write to:" << toProcNo
+        Perr<< "UOPstream::write : starting write to:" << toProcNo
             << " size:" << label(bufSize)
             << " tag:" << tag << " comm:" << communicator
             << " commType:" << UPstream::commsTypeNames[commsType]
@@ -114,7 +114,7 @@ bool Foam::UOPstream::write
 
         if (UPstream::debug)
         {
-            Pout<< "UOPstream::write : finished buffered send to:"
+            Perr<< "UOPstream::write : finished buffered send to:"
                 << toProcNo
                 << " size:" << label(bufSize) << " tag:" << tag
                 << Foam::endl;
@@ -152,7 +152,7 @@ bool Foam::UOPstream::write
 
         if (UPstream::debug)
         {
-            Pout<< "UOPstream::write : finished send to:"
+            Perr<< "UOPstream::write : finished send to:"
                 << toProcNo
                 << " size:" << label(bufSize) << " tag:" << tag
                 << Foam::endl;
@@ -191,7 +191,7 @@ bool Foam::UOPstream::write
 
         if (UPstream::debug)
         {
-            Pout<< "UOPstream::write : started non-blocking send to:"
+            Perr<< "UOPstream::write : started non-blocking send to:"
                 << toProcNo
                 << " size:" << label(bufSize) << " tag:" << tag
                 << " request:" <<
diff --git a/src/Pstream/mpi/UPstream.C b/src/Pstream/mpi/UPstream.C
index b23c85d66c..b3771d7d1e 100644
--- a/src/Pstream/mpi/UPstream.C
+++ b/src/Pstream/mpi/UPstream.C
@@ -90,13 +90,13 @@ static void attachOurBuffers()
 
         if (Foam::UPstream::debug)
         {
-            Foam::Pout<< "UPstream::init : buffer-size " << len << '\n';
+            Foam::Perr<< "UPstream::init : buffer-size " << len << '\n';
         }
     }
     else
     {
         delete[] buf;
-        Foam::Pout<< "UPstream::init : could not attach buffer\n";
+        Foam::Perr<< "UPstream::init : could not attach buffer\n";
     }
 #endif
 }
@@ -171,7 +171,7 @@ bool Foam::UPstream::initNull()
     {
         if (UPstream::debug)
         {
-            Pout<< "UPstream::initNull : was already initialized\n";
+            Perr<< "UPstream::initNull : was already initialized\n";
         }
     }
     else
@@ -229,7 +229,7 @@ bool Foam::UPstream::init(int& argc, char**& argv, const bool needsThread)
         }
         else if (UPstream::debug)
         {
-            Pout<< "UPstream::init : was already initialized\n";
+            Perr<< "UPstream::init : was already initialized\n";
         }
     }
     else
@@ -283,7 +283,7 @@ bool Foam::UPstream::init(int& argc, char**& argv, const bool needsThread)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::init :"
+        Perr<< "UPstream::init :"
             << " thread-support : requested:" << needsThread
             << " obtained:"
             << (
@@ -390,7 +390,7 @@ bool Foam::UPstream::init(int& argc, char**& argv, const bool needsThread)
                 &subRank
             );
 
-            Pout<< "UPstream::init : in world:" << world
+            Perr<< "UPstream::init : in world:" << world
                 << " using local communicator:" << subComm
                 << " rank " << subRank
                 << " of " << subNumProcs
@@ -436,7 +436,7 @@ void Foam::UPstream::shutdown(int errNo)
         }
         else if (UPstream::debug && errNo == 0)
         {
-            Pout<< "UPstream::shutdown : was already finalized\n";
+            Perr<< "UPstream::shutdown : was already finalized\n";
         }
         ourMpi = false;
         return;
@@ -465,7 +465,7 @@ void Foam::UPstream::shutdown(int errNo)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::shutdown\n";
+        Perr<< "UPstream::shutdown\n";
     }
 
     // Check for any outstanding requests
@@ -691,7 +691,7 @@ void Foam::UPstream::freeCommunicatorComponents(const label index)
 {
     if (UPstream::debug)
     {
-        Pout<< "freeCommunicatorComponents: " << index
+        Perr<< "freeCommunicatorComponents: " << index
             << " from " << PstreamGlobals::MPICommunicators_.size() << endl;
     }
 
diff --git a/src/Pstream/mpi/UPstreamBroadcast.C b/src/Pstream/mpi/UPstreamBroadcast.C
index f3b7fac7d4..dcf9ca8ed9 100644
--- a/src/Pstream/mpi/UPstreamBroadcast.C
+++ b/src/Pstream/mpi/UPstreamBroadcast.C
@@ -49,16 +49,16 @@ bool Foam::UPstream::broadcast
 
     if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
-        Pout<< "UPstream::broadcast : root:" << rootProcNo
+        Perr<< "UPstream::broadcast : root:" << rootProcNo
             << " comm:" << comm
             << " size:" << label(bufSize)
             << " warnComm:" << UPstream::warnComm
             << Foam::endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
     else if (UPstream::debug)
     {
-        Pout<< "UPstream::broadcast : root:" << rootProcNo
+        Perr<< "UPstream::broadcast : root:" << rootProcNo
             << " comm:" << comm
             << " size:" << label(bufSize)
             << Foam::endl;
diff --git a/src/Pstream/mpi/UPstreamRequest.C b/src/Pstream/mpi/UPstreamRequest.C
index 04947e2028..3ac8b8ff8a 100644
--- a/src/Pstream/mpi/UPstreamRequest.C
+++ b/src/Pstream/mpi/UPstreamRequest.C
@@ -291,7 +291,7 @@ void Foam::UPstream::waitRequests(const label pos, label len)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::waitRequests : starting wait for "
+        Perr<< "UPstream::waitRequests : starting wait for "
             << count << " requests starting at " << pos << endl;
     }
 
@@ -328,7 +328,7 @@ void Foam::UPstream::waitRequests(const label pos, label len)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::waitRequests : finished wait." << endl;
+        Perr<< "UPstream::waitRequests : finished wait." << endl;
     }
 }
 
@@ -409,7 +409,7 @@ bool Foam::UPstream::waitAnyRequest(const label pos, label len)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::waitAnyRequest : starting wait for any of "
+        Perr<< "UPstream::waitAnyRequest : starting wait for any of "
             << count << " requests starting at " << pos << endl;
     }
 
@@ -470,7 +470,7 @@ bool Foam::UPstream::waitSomeRequests
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream:waitSomeRequest : starting wait for some of "
+        Perr<< "UPstream:waitSomeRequest : starting wait for some of "
             << count << " requests starting at " << pos << endl;
     }
 
@@ -563,7 +563,7 @@ bool Foam::UPstream::waitSomeRequests
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream:waitSomeRequest : starting wait for some of "
+        Perr<< "UPstream:waitSomeRequest : starting wait for some of "
             << requests.size() << " requests" << endl;
     }
 
@@ -753,7 +753,7 @@ void Foam::UPstream::waitRequest(const label i)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::waitRequest : starting wait for request:"
+        Perr<< "UPstream::waitRequest : starting wait for request:"
             << i << endl;
     }
 
@@ -771,7 +771,7 @@ void Foam::UPstream::waitRequest(const label i)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::waitRequest : finished wait for request:"
+        Perr<< "UPstream::waitRequest : finished wait for request:"
             << i << endl;
     }
 }
@@ -823,7 +823,7 @@ bool Foam::UPstream::finishedRequest(const label i)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::finishedRequest : check request:"
+        Perr<< "UPstream::finishedRequest : check request:"
             << i << endl;
     }
 
@@ -898,7 +898,7 @@ bool Foam::UPstream::finishedRequests(const label pos, label len)
 
     if (UPstream::debug)
     {
-        Pout<< "UPstream::finishedRequests : check " << count
+        Perr<< "UPstream::finishedRequests : check " << count
             << " requests starting at " << pos << endl;
     }
 
diff --git a/src/Pstream/mpi/UPstreamWrapping.txx b/src/Pstream/mpi/UPstreamWrapping.txx
index 94fc3025e1..97b0a95b4c 100644
--- a/src/Pstream/mpi/UPstreamWrapping.txx
+++ b/src/Pstream/mpi/UPstreamWrapping.txx
@@ -80,18 +80,18 @@ void Foam::PstreamDetail::reduce0
 
     if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
-        Pout<< "** MPI_Reduce (blocking):";
+        Perr<< "** MPI_Reduce (blocking):";
         if (count == 1)
         {
-            Pout<< (*values);
+            Perr<< (*values);
         }
         else
         {
-            Pout<< UList<Type>(values, count);
+            Perr<< UList<Type>(values, count);
         }
-        Pout<< " with comm:" << comm
+        Perr<< " with comm:" << comm
             << " warnComm:" << UPstream::warnComm << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     profilingPstream::beginTiming();
@@ -138,23 +138,23 @@ void Foam::PstreamDetail::allReduce
     {
         if (immediate)
         {
-            Pout<< "** MPI_Iallreduce (non-blocking):";
+            Perr<< "** MPI_Iallreduce (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Allreduce (blocking):";
+            Perr<< "** MPI_Allreduce (blocking):";
         }
         if (count == 1)
         {
-            Pout<< (*values);
+            Perr<< (*values);
         }
         else
         {
-            Pout<< UList<Type>(values, count);
+            Perr<< UList<Type>(values, count);
         }
-        Pout<< " with comm:" << comm
+        Perr<< " with comm:" << comm
             << " warnComm:" << UPstream::warnComm << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
 
@@ -245,18 +245,18 @@ void Foam::PstreamDetail::allToAll
     {
         if (immediate)
         {
-            Pout<< "** MPI_Ialltoall (non-blocking):";
+            Perr<< "** MPI_Ialltoall (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Alltoall (blocking):";
+            Perr<< "** MPI_Alltoall (blocking):";
         }
-        Pout<< " numProc:" << numProc
+        Perr<< " numProc:" << numProc
             << " sendData:" << sendData.size()
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     if
@@ -376,18 +376,18 @@ void Foam::PstreamDetail::allToAllv
     {
         if (immediate)
         {
-            Pout<< "** MPI_Ialltoallv (non-blocking):";
+            Perr<< "** MPI_Ialltoallv (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Alltoallv (blocking):";
+            Perr<< "** MPI_Alltoallv (blocking):";
         }
-        Pout<< " sendCounts:" << sendCounts
+        Perr<< " sendCounts:" << sendCounts
             << " sendOffsets:" << sendOffsets
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     if
@@ -515,13 +515,13 @@ void Foam::PstreamDetail::allToAllConsensus
 
     if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
-        Pout<< "** non-blocking consensus Alltoall (list):";
-        Pout<< " numProc:" << numProc
+        Perr<< "** non-blocking consensus Alltoall (list):";
+        Perr<< " numProc:" << numProc
             << " sendData:" << sendData.size()
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     if (sendData.size() != numProc || recvData.size() != numProc)
@@ -717,13 +717,13 @@ void Foam::PstreamDetail::allToAllConsensus
 
     if (UPstream::warnComm >= 0 && comm != UPstream::warnComm)
     {
-        Pout<< "** non-blocking consensus Alltoall (map):";
-        Pout<< " numProc:" << numProc
+        Perr<< "** non-blocking consensus Alltoall (map):";
+        Perr<< " numProc:" << numProc
             << " sendData:" << sendBufs.size()
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     // Initial: clear out everything
@@ -917,18 +917,18 @@ void Foam::PstreamDetail::gather
     {
         if (immediate)
         {
-            Pout<< "** MPI_Igather (non-blocking):";
+            Perr<< "** MPI_Igather (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Gather (blocking):";
+            Perr<< "** MPI_Gather (blocking):";
         }
-        Pout<< " numProc:" << numProc
+        Perr<< " numProc:" << numProc
             << " count:" << count
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
 
@@ -1024,18 +1024,18 @@ void Foam::PstreamDetail::scatter
     {
         if (immediate)
         {
-            Pout<< "** MPI_Iscatter (non-blocking):";
+            Perr<< "** MPI_Iscatter (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Scatter (blocking):";
+            Perr<< "** MPI_Scatter (blocking):";
         }
-        Pout<< " numProc:" << numProc
+        Perr<< " numProc:" << numProc
             << " count:" << count
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
 
@@ -1132,19 +1132,19 @@ void Foam::PstreamDetail::gatherv
     {
         if (immediate)
         {
-            Pout<< "** MPI_Igatherv (non-blocking):";
+            Perr<< "** MPI_Igatherv (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Gatherv (blocking):";
+            Perr<< "** MPI_Gatherv (blocking):";
         }
-        Pout<< " np:" << np
+        Perr<< " np:" << np
             << " recvCounts:" << recvCounts
             << " recvOffsets:" << recvOffsets
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     if
@@ -1274,19 +1274,19 @@ void Foam::PstreamDetail::scatterv
     {
         if (immediate)
         {
-            Pout<< "** MPI_Iscatterv (non-blocking):";
+            Perr<< "** MPI_Iscatterv (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Scatterv (blocking):";
+            Perr<< "** MPI_Scatterv (blocking):";
         }
-        Pout<< " np:" << np
+        Perr<< " np:" << np
             << " sendCounts:" << sendCounts
             << " sendOffsets:" << sendOffsets
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }
 
     if
@@ -1400,17 +1400,17 @@ void Foam::PstreamDetail::allGather
     {
         if (immediate)
         {
-            Pout<< "** MPI_Iallgather (non-blocking):";
+            Perr<< "** MPI_Iallgather (non-blocking):";
         }
         else
         {
-            Pout<< "** MPI_Allgather (blocking):";
+            Perr<< "** MPI_Allgather (blocking):";
         }
-        Pout<< " numProc:" << UPstream::nProcs(comm)
+        Perr<< " numProc:" << UPstream::nProcs(comm)
             << " with comm:" << comm
             << " warnComm:" << UPstream::warnComm
             << endl;
-        error::printStack(Pout);
+        error::printStack(Perr);
     }