diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0d1b26a..a126730 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,7 @@
 ###############################################################################
 # MONIO - Met Office NetCDF Input Output                                      #
 #                                                                             #
-# (C) Crown Copyright 2023 Met Office                                         #
+# (C) Crown Copyright 2023, Met Office.                                       #
 #                                                                             #
 # This software is licensed under the terms of the Apache Licence Version 2.0 #
 # which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
diff --git a/ci/CMakeLists.txt b/ci/CMakeLists.txt
index 0728893..c36f6bf 100644
--- a/ci/CMakeLists.txt
+++ b/ci/CMakeLists.txt
@@ -1,3 +1,12 @@
+###############################################################################
+# MONIO - Met Office NetCDF Input Output                                      #
+#                                                                             #
+# (C) Crown Copyright 2023, Met Office.                                       #
+#                                                                             #
+# This software is licensed under the terms of the Apache Licence Version 2.0 #
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
+###############################################################################
+
 cmake_minimum_required( VERSION 3.20 FATAL_ERROR )
 
 project( monio-ci VERSION 0.0.1 LANGUAGES C CXX Fortran )
diff --git a/ci/build-and-lint b/ci/build-and-lint
index ce6653e..b25c8b1 100755
--- a/ci/build-and-lint
+++ b/ci/build-and-lint
@@ -1,7 +1,12 @@
 #!/bin/bash
-#
-# (C) Crown Copyright 2023, the Met Office. All rights reserved.
-#
+###############################################################################
+# MONIO - Met Office NetCDF Input Output                                      #
+#                                                                             #
+# (C) Crown Copyright 2023, Met Office.                                       #
+#                                                                             #
+# This software is licensed under the terms of the Apache Licence Version 2.0 #
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
+###############################################################################
 set -euo pipefail
 
 finally() {
diff --git a/ci/build-and-test b/ci/build-and-test
index 71844e2..de7bf90 100755
--- a/ci/build-and-test
+++ b/ci/build-and-test
@@ -1,7 +1,12 @@
 #!/bin/bash
-#
-# (C) Crown Copyright 2023, the Met Office. All rights reserved.
-#
+###############################################################################
+# MONIO - Met Office NetCDF Input Output                                      #
+#                                                                             #
+# (C) Crown Copyright 2023, Met Office.                                       #
+#                                                                             #
+# This software is licensed under the terms of the Apache Licence Version 2.0 #
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
+###############################################################################
 set -euxo pipefail
 
 finally() {
diff --git a/ci/get-ref-branch b/ci/get-ref-branch
index 3ce3028..5ed7616 100755
--- a/ci/get-ref-branch
+++ b/ci/get-ref-branch
@@ -1,4 +1,12 @@
 #!/bin/bash
+###############################################################################
+# MONIO - Met Office NetCDF Input Output                                      #
+#                                                                             #
+# (C) Crown Copyright 2023, Met Office.                                       #
+#                                                                             #
+# This software is licensed under the terms of the Apache Licence Version 2.0 #
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
+###############################################################################
 set -euxo pipefail
 repo="$1"  # expect path to a repo clone
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 84f4966..c9741fb 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,7 +1,7 @@
 ###############################################################################
 # MONIO - Met Office NetCDF Input Output                                      #
 #                                                                             #
-# (C) Crown Copyright 2023 Met Office                                         #
+# (C) Crown Copyright 2023, Met Office.                                       #
 #                                                                             #
 # This software is licensed under the terms of the Apache Licence Version 2.0 #
 # which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
diff --git a/src/monio/AtlasReader.cc b/src/monio/AtlasReader.cc
index 3d34676..e893c31 100644
--- a/src/monio/AtlasReader.cc
+++ b/src/monio/AtlasReader.cc
@@ -12,6 +12,7 @@
 
 #include "Utils.h"
 #include "UtilsAtlas.h"
+#include "Monio.h"
 
 monio::AtlasReader::AtlasReader(const eckit::mpi::Comm& mpiCommunicator,
                                     const int mpiRankOwner):
@@ -59,6 +60,7 @@ void monio::AtlasReader::populateFieldWithDataContainer(atlas::Field& field,
       break;
     }
     default: {
+        Monio::get().closeFiles();
         utils::throwException("AtlasReader::populateFieldWithDataContainer()> "
                                  "Data type not coded for...");
       }
@@ -91,6 +93,7 @@ void monio::AtlasReader::populateFieldWithDataContainer(atlas::Field& field,
       break;
     }
     default: {
+        Monio::get().closeFiles();
         utils::throwException("AtlasReader::populateFieldWithDataContainer()> "
                                  "Data type not coded for...");
       }
@@ -107,6 +110,7 @@ void monio::AtlasReader::populateField(atlas::Field& field,
   auto fieldView = atlas::array::make_view<T, 2>(field);
   // Field with noFirstLevel == true should have been adjusted to have 70 levels.
   if (noFirstLevel == true && field.levels() == consts::kVerticalFullSize) {
+    Monio::get().closeFiles();
     utils::throwException("AtlasReader::populateField()> Field levels misconfiguration...");
   // Only valid case for field with noFirstLevel == true. Field is adjusted to have 70 levels but
   // read data still has enough to fill 71.
@@ -118,6 +122,7 @@ void monio::AtlasReader::populateField(atlas::Field& field,
         if (std::size_t(index) <= dataVec.size()) {
           fieldView(i, j - 1) = dataVec[index];
         } else {
+          Monio::get().closeFiles();
           utils::throwException("AtlasReader::populateField()> Calculated index exceeds size of "
                                 "data for field \"" + field.name() + "\".");
         }
@@ -132,6 +137,7 @@ void monio::AtlasReader::populateField(atlas::Field& field,
         if (std::size_t(index) <= dataVec.size()) {
           fieldView(i, j) = dataVec[index];
         } else {
+          Monio::get().closeFiles();
           utils::throwException("AtlasReader::populateField()> Calculated index exceeds size of "
                                 "data for field \"" + field.name() + "\".");
         }
@@ -170,6 +176,7 @@ void monio::AtlasReader::populateField(atlas::Field& field,
       if (std::size_t(index) <= dataVec.size()) {
         fieldView(i, j) = dataVec[index];
       } else {
+        Monio::get().closeFiles();
         utils::throwException("AtlasReader::populateField()> "
                               "Calculated index exceeds size of data.");
       }
@@ -192,6 +199,7 @@ atlas::Field monio::AtlasReader::getReadField(atlas::Field& field,
     if (atlasType != atlasType.KIND_REAL64 &&
         atlasType != atlasType.KIND_REAL32 &&
         atlasType != atlasType.KIND_INT32) {
+        Monio::get().closeFiles();
         utils::throwException("AtlasReader::getReadField())> Data type not coded for...");
     }
     atlas::util::Config atlasOptions = atlas::option::name(field.name()) |
diff --git a/src/monio/AtlasWriter.cc b/src/monio/AtlasWriter.cc
index 938c93f..a98ed43 100644
--- a/src/monio/AtlasWriter.cc
+++ b/src/monio/AtlasWriter.cc
@@ -17,6 +17,7 @@
 #include "DataContainerFloat.h"
 #include "DataContainerInt.h"
 #include "Metadata.h"
+#include "Monio.h"
 #include "Utils.h"
 #include "UtilsAtlas.h"
 #include "Writer.h"
@@ -202,7 +203,8 @@ void monio::AtlasWriter::populateDataContainerWithField(
         break;
       }
       default: {
-        utils::throwException("AtlasWriter::populateDataContainerWithField()> "
+        Monio::get().closeFiles();
+utils::throwException("AtlasWriter::populateDataContainerWithField()> "
                                  "Data type not coded for...");
       }
     }
@@ -254,7 +256,8 @@ void monio::AtlasWriter::populateDataContainerWithField(
       break;
     }
     default: {
-        utils::throwException("AtlasWriter::populateDataContainerWithField()> "
+        Monio::get().closeFiles();
+utils::throwException("AtlasWriter::populateDataContainerWithField()> "
                                  "Data type not coded for...");
       }
     }
@@ -268,7 +271,8 @@ void monio::AtlasWriter::populateDataVec(std::vector<T>& dataVec,
   oops::Log::debug() << "AtlasWriter::populateDataVec() " << field.name() << std::endl;
   int numLevels = field.levels();
   if ((lfricToAtlasMap.size() * numLevels) != dataVec.size()) {
-    utils::throwException("AtlasWriter::populateDataVec()> "
+    Monio::get().closeFiles();
+utils::throwException("AtlasWriter::populateDataVec()> "
                           "Data container is not configured for the expected data...");
   }
   auto fieldView = atlas::array::make_view<T, 2>(field);
@@ -323,10 +327,12 @@ atlas::Field monio::AtlasWriter::getWriteField(atlas::Field& field,
   if (atlasType != atlasType.KIND_REAL64 &&
       atlasType != atlasType.KIND_REAL32 &&
       atlasType != atlasType.KIND_INT32) {
+      Monio::get().closeFiles();
       utils::throwException("AtlasWriter::getWriteField())> Data type not coded for...");
   }
   // Erroneous case. For noFirstLevel == true field should have 70 levels
   if (noFirstLevel == true && field.levels() == consts::kVerticalFullSize) {
+    Monio::get().closeFiles();
     utils::throwException("AtlasWriter::getWriteField()> Field levels misconfiguration...");
   }
   // WARNING - This name-check is an LFRic-Lite specific convention...
@@ -350,6 +356,7 @@ atlas::Field monio::AtlasWriter::getWriteField(atlas::Field& field,
       field.metadata().set("name", writeName);
     }
   } else {
+    Monio::get().closeFiles();
     utils::throwException("AtlasWriter::getWriteField()> Field write name misconfiguration...");
   }
   return field;
diff --git a/src/monio/AtlasWriter.h b/src/monio/AtlasWriter.h
index 3e96b25..5f066b7 100644
--- a/src/monio/AtlasWriter.h
+++ b/src/monio/AtlasWriter.h
@@ -1,10 +1,10 @@
 /******************************************************************************
 * MONIO - Met Office NetCDF Input Output                                      *
 *                                                                             *
-* (C) Crown Copyright 2023, Met Office. All rights reserved.                  *
+* (C) Crown Copyright 2023 Met Office                                         *
 *                                                                             *
-* This software is licensed under the terms of the 3-Clause BSD License       *
-* which can be obtained from https://opensource.org/license/bsd-3-clause/.    *
+* This software is licensed under the terms of the Apache Licence Version 2.0 *
+* which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        *
 ******************************************************************************/
 #pragma once
 
diff --git a/src/monio/Data.cc b/src/monio/Data.cc
index a5df14b..37d388e 100644
--- a/src/monio/Data.cc
+++ b/src/monio/Data.cc
@@ -17,6 +17,7 @@
 #include "DataContainerDouble.h"
 #include "DataContainerFloat.h"
 #include "DataContainerInt.h"
+#include "Monio.h"
 #include "Utils.h"
 
 namespace {
@@ -142,6 +143,7 @@ std::shared_ptr<monio::DataContainerBase>
   if (it != dataContainers_.end()) {
     return it->second;
   } else {
+    Monio::get().closeFiles();
     utils::throwException("DataContainer named \"" + name + "\" was not found.");
   }
 }
diff --git a/src/monio/DataContainerDouble.cc b/src/monio/DataContainerDouble.cc
index a281f1b..855b438 100644
--- a/src/monio/DataContainerDouble.cc
+++ b/src/monio/DataContainerDouble.cc
@@ -11,6 +11,7 @@
 #include <stdexcept>
 
 #include "Constants.h"
+#include "Monio.h"
 #include "Utils.h"
 
 monio::DataContainerDouble::DataContainerDouble(const std::string& name) :
@@ -30,6 +31,7 @@ const std::vector<double>& monio::DataContainerDouble::getData() const {
 
 const double& monio::DataContainerDouble::getDatum(const size_t index) {
   if (index > dataVector_.size()) {
+    Monio::get().closeFiles();
     utils::throwException("DataContainerDouble::getDatum()> Passed index exceeds vector size...");
   }
 
diff --git a/src/monio/DataContainerFloat.cc b/src/monio/DataContainerFloat.cc
index 772a349..c598987 100644
--- a/src/monio/DataContainerFloat.cc
+++ b/src/monio/DataContainerFloat.cc
@@ -11,6 +11,7 @@
 #include <stdexcept>
 
 #include "Constants.h"
+#include "Monio.h"
 #include "Utils.h"
 
 monio::DataContainerFloat::DataContainerFloat(const std::string& name) :
@@ -30,6 +31,7 @@ const std::vector<float>& monio::DataContainerFloat::getData() const {
 
 const float& monio::DataContainerFloat::getDatum(const size_t index) {
   if (index > dataVector_.size()) {
+    Monio::get().closeFiles();
     utils::throwException("DataContainerFloat::getDatum()> Passed index exceeds vector size...");
   }
   return dataVector_[index];
diff --git a/src/monio/DataContainerInt.cc b/src/monio/DataContainerInt.cc
index 89ca2dd..218213c 100644
--- a/src/monio/DataContainerInt.cc
+++ b/src/monio/DataContainerInt.cc
@@ -11,6 +11,7 @@
 #include <stdexcept>
 
 #include "Constants.h"
+#include "Monio.h"
 #include "Utils.h"
 
 monio::DataContainerInt::DataContainerInt(const std::string& name) :
@@ -30,6 +31,7 @@ const std::vector<int>& monio::DataContainerInt::getData() const {
 
 const int& monio::DataContainerInt::getDatum(const size_t index) {
   if (index > dataVector_.size()) {
+    Monio::get().closeFiles();
     utils::throwException("DataContainerInt::getDatum()> Passed index exceeds vector size...");
   }
   return dataVector_[index];
diff --git a/src/monio/File.cc b/src/monio/File.cc
index 5221101..f25eb30 100644
--- a/src/monio/File.cc
+++ b/src/monio/File.cc
@@ -254,8 +254,8 @@ void monio::File::readAttributes(Metadata& metadata) {
       metadata.addGlobalAttr(globAttr->getName(), globAttr);
     }
   } else {
-    utils::throwException(
-        "File::readAttributes()> Write file accessed for reading...");
+    close();
+    utils::throwException("File::readAttributes()> Write file accessed for reading...");
   }
 }
 
diff --git a/src/monio/Metadata.cc b/src/monio/Metadata.cc
index ac00ade..4d82321 100644
--- a/src/monio/Metadata.cc
+++ b/src/monio/Metadata.cc
@@ -20,6 +20,7 @@
 #include "AttributeDouble.h"
 #include "AttributeInt.h"
 #include "AttributeString.h"
+#include "Monio.h"
 #include "Utils.h"
 
 monio::Metadata::Metadata() {
@@ -142,6 +143,7 @@ int monio::Metadata::getDimension(const std::string& dimName) {
   if (isDimDefined(dimName) == true) {
     return dimensions_.at(dimName);
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Metadata::getDimension()> dimension \"" + dimName + "\" not found...");
   }
 }
@@ -170,6 +172,7 @@ std::shared_ptr<monio::Variable> monio::Metadata::getVariable(const std::string&
   if (it != variables_.end()) {
     return variables_.at(varName);
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Metadata::getVariable()> variable \"" + varName + "\" not found...");
   }
 }
@@ -182,6 +185,7 @@ const std::shared_ptr<monio::Variable>
   if (it != variables_.end()) {
     return variables_.at(varName);
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Metadata::getVariable()> variable \"" + varName + "\" not found...");
   }
 }
@@ -223,6 +227,7 @@ const std::vector<std::string> monio::Metadata::getVarStrAttrs(
       varStrAttrs.push_back(attr);
   }
   if (varNames.size() != varStrAttrs.size()) {
+    Monio::get().closeFiles();
     utils::throwException("Metadata::getVarStrAttrs()> "
         "Unmatched number of variables and attributes...");
   }
@@ -361,6 +366,7 @@ void monio::Metadata::deleteVariable(const std::string& varName) {
   if (it != variables_.end()) {
     variables_.erase(varName);
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Metadata::deleteVariable()> Variable \"" + varName + "\" not found...");
   }
 }
@@ -432,6 +438,7 @@ void monio::Metadata::printVariables() {
           break;
         }
         default: {
+          Monio::get().closeFiles();
           utils::throwException("Metadata::printGlobalAttrs()> Data type not coded for...");
         }
       }
@@ -464,6 +471,7 @@ void monio::Metadata::printGlobalAttrs() {
         break;
       }
       default: {
+        Monio::get().closeFiles();
         utils::throwException("Metadata::printGlobalAttrs()> Data type not coded for...");
       }
     }
diff --git a/src/monio/Monio.cc b/src/monio/Monio.cc
index a9553e2..1c885ef 100644
--- a/src/monio/Monio.cc
+++ b/src/monio/Monio.cc
@@ -48,6 +48,7 @@ void monio::Monio::readState(atlas::FieldSet& localFieldSet,
                             const util::DateTime& dateTime) {
   oops::Log::debug() << "Monio::readState()" << std::endl;
   if (localFieldSet.size() == 0) {
+    Monio::get().closeFiles();
     utils::throwException("Monio::readState()> localFieldSet has zero fields...");
   }
   if (filePath.length() != 0) {
@@ -85,12 +86,15 @@ void monio::Monio::readState(atlas::FieldSet& localFieldSet,
       } catch (netCDF::exceptions::NcException& exception) {
         reader_.closeFile();
         std::string exceptionMessage = exception.what();
+        Monio::get().closeFiles();
         utils::throwException("Monio::readState()> An exception has occurred: " + exceptionMessage);
       }
     } else {
+      Monio::get().closeFiles();
       utils::throwException("Monio::readState()> File \"" + filePath + "\" does not exist...");
     }
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Monio::readState()> No file path supplied...");
   }
 }
@@ -100,6 +104,7 @@ void monio::Monio::readIncrements(atlas::FieldSet& localFieldSet,
                             const std::string& filePath) {
   oops::Log::debug() << "Monio::readIncrements()" << std::endl;
   if (localFieldSet.size() == 0) {
+    Monio::get().closeFiles();
     utils::throwException("Monio::readIncrements()> localFieldSet has zero fields...");
   }
   if (filePath.length() != 0) {
@@ -137,13 +142,16 @@ void monio::Monio::readIncrements(atlas::FieldSet& localFieldSet,
         oops::Log::info() << " exception.what()> " <<  exception.what() << std::endl;
         reader_.closeFile();
         std::string exceptionMessage = exception.what();
+        Monio::get().closeFiles();
         utils::throwException("Monio::readIncrements()> An exception has occurred: " +
                               exceptionMessage);
       }
     } else {
+      Monio::get().closeFiles();
       utils::throwException("Monio::readIncrements()> File \"" + filePath + "\" does not exist...");
     }
   } else {
+    Monio::get().closeFiles();
     utils::throwException("Monio::readIncrements()> No file path supplied...");
   }
 }
@@ -154,6 +162,7 @@ void monio::Monio::writeIncrements(const atlas::FieldSet& localFieldSet,
                                    const bool isLfricNaming) {
   oops::Log::debug() << "Monio::writeIncrements()" << std::endl;
   if (localFieldSet.size() == 0) {
+    Monio::get().closeFiles();
     utils::throwException("Monio::writeIncrements()> localFieldSet has zero fields...");
   }
   if (filePath.length() != 0) {
@@ -174,6 +183,7 @@ void monio::Monio::writeIncrements(const atlas::FieldSet& localFieldSet,
           } else if (isLfricNaming == false && fieldMetadata.jediName == globalField.name()) {
             writeName = fieldMetadata.jediName;
           } else {
+            Monio::get().closeFiles();
             utils::throwException("Monio::writeIncrements()> "
                                   "Field metadata configuration error...");
           }
@@ -194,6 +204,7 @@ void monio::Monio::writeIncrements(const atlas::FieldSet& localFieldSet,
     } catch (netCDF::exceptions::NcException& exception) {
       writer_.closeFile();
       std::string exceptionMessage = exception.what();
+      Monio::get().closeFiles();
       utils::throwException("Monio::writeIncrements()> An exception occurred: " + exceptionMessage);
     }
   } else {
@@ -208,6 +219,7 @@ void monio::Monio::writeState(const atlas::FieldSet& localFieldSet,
                               const bool isLfricNaming) {
   oops::Log::debug() << "Monio::writeState()" << std::endl;
   if (localFieldSet.size() == 0) {
+    Monio::get().closeFiles();
     utils::throwException("Monio::writeState()> localFieldSet has zero fields...");
   }
   if (filePath.length() != 0) {
@@ -228,6 +240,7 @@ void monio::Monio::writeState(const atlas::FieldSet& localFieldSet,
           } else if (isLfricNaming == false && fieldMetadata.jediName == globalField.name()) {
             writeName = fieldMetadata.jediName;
           } else {
+            Monio::get().closeFiles();
             utils::throwException("Monio::writeState()> Field metadata configuration error...");
           }
           oops::Log::debug() << "Monio::writeState() processing data for> \"" <<
@@ -247,6 +260,7 @@ void monio::Monio::writeState(const atlas::FieldSet& localFieldSet,
     } catch (netCDF::exceptions::NcException& exception) {
       writer_.closeFile();
       std::string exceptionMessage = exception.what();
+      Monio::get().closeFiles();
       utils::throwException("Monio::writeState()> An exception has occurred: " + exceptionMessage);
     }
   } else {
@@ -259,6 +273,7 @@ void monio::Monio::writeFieldSet(const atlas::FieldSet& localFieldSet,
                                  const std::string& filePath) {
   oops::Log::debug() << "Monio::writeFieldSet()" << std::endl;
   if (localFieldSet.size() == 0) {
+    Monio::get().closeFiles();
     utils::throwException("Monio::writeFieldSet()> localFieldSet has zero fields...");
   }
   if (filePath.length() != 0) {
@@ -278,6 +293,7 @@ void monio::Monio::writeFieldSet(const atlas::FieldSet& localFieldSet,
     } catch (netCDF::exceptions::NcException& exception) {
       writer_.closeFile();
       std::string exceptionMessage = exception.what();
+      Monio::get().closeFiles();
       utils::throwException("Monio::writeFieldSet()> An exception occurred: " + exceptionMessage);
     }
   } else {
@@ -369,10 +385,10 @@ void monio::Monio::createDateTimes(FileData& fileData,
       std::shared_ptr<Variable> timeVar = fileData.getMetadata().getVariable(timeVarName);
       std::shared_ptr<DataContainerBase> timeDataBase =
                                              fileData.getData().getContainer(timeVarName);
-      if (timeDataBase->getType() != consts::eDouble)
-        utils::throwException("Monio::createDateTimes()> "
-                                 "Time data not stored as double...");
-
+      if (timeDataBase->getType() != consts::eDouble) {
+        Monio::get().closeFiles();
+        utils::throwException("Monio::createDateTimes()> Time data not stored as double...");
+      }
       std::shared_ptr<DataContainerDouble> timeData =
                   std::static_pointer_cast<DataContainerDouble>(timeDataBase);
 
diff --git a/src/monio/Reader.cc b/src/monio/Reader.cc
index a8ae4b3..7499172 100644
--- a/src/monio/Reader.cc
+++ b/src/monio/Reader.cc
@@ -259,6 +259,7 @@ size_t monio::Reader::findTimeStep(const FileData& fileData, const util::DateTim
   oops::Log::debug() << "Reader::findTimeStep()" << std::endl;
   if (fileData.getDateTimes().size() == 0) {
     oops::Log::debug() << "Reader::findTimeStep()> Date times not initialised..." << std::endl;
+    closeFile();
     utils::throwException("Reader::findTimeStep()> Date times not initialised...");
   }
 
diff --git a/src/monio/UtilsAtlas.cc b/src/monio/UtilsAtlas.cc
index be7a53e..68526ac 100644
--- a/src/monio/UtilsAtlas.cc
+++ b/src/monio/UtilsAtlas.cc
@@ -19,6 +19,7 @@
 
 #include "DataContainerDouble.h"
 #include "DataContainerFloat.h"
+#include "Monio.h"
 #include "Utils.h"
 
 namespace monio {
@@ -38,8 +39,8 @@ std::vector<atlas::PointLonLat> getLfricCoords(
         coordVectorArray[coordCount] = coordData;
         coordCount++;
       } else {
-        utils::throwException("utilsatlas::getLfricCoords()> "
-            "Data type not coded for...");
+        Monio::get().closeFiles();
+        utils::throwException("utilsatlas::getLfricCoords()> Data type not coded for...");
       }
     }
     // Populate Atlas PointLonLat vector
@@ -49,6 +50,7 @@ std::vector<atlas::PointLonLat> getLfricCoords(
       lfricCoords.push_back(atlas::PointLonLat(*lonIt, *latIt));
     }
   } else {
+      Monio::get().closeFiles();
       utils::throwException("utilsatlas::getLfricCoords()> "
           "Incorrect number of coordinate axes...");
   }
@@ -100,6 +102,7 @@ std::vector<size_t> createLfricAtlasMap(const std::vector<atlas::PointLonLat>& a
   std::vector<size_t> lfricAtlasMap;
   // Essential check to ensure grid is configured to accommodate the data
   if (atlasCoords.size() != lfricCoords.size()) {
+    Monio::get().closeFiles();
     utils::throwException("utilsatlas::createLfricAtlasMap()> "
       "Configured grid is not compatible with input file...");
   }
@@ -135,6 +138,7 @@ atlas::Field getGlobalField(const atlas::Field& field) {
     if (atlasType != atlasType.KIND_REAL64 &&
         atlasType != atlasType.KIND_REAL32 &&
         atlasType != atlasType.KIND_INT32) {
+        Monio::get().closeFiles();
         utils::throwException("utilsatlas::getGlobalFieldSet())> Data type not coded for...");
     }
     const auto& functionSpace = field.functionspace();
@@ -155,6 +159,7 @@ atlas::FieldSet getGlobalFieldSet(const atlas::FieldSet& fieldSet) {
     }
     return globalFieldSet;
   } else {
+    Monio::get().closeFiles();
     utils::throwException("utilsatlas::getGlobalFieldSet()> FieldSet has zero fields...");
   }
 }
@@ -183,17 +188,19 @@ int getGlobalDataSize(const atlas::Field& field) {
 
 int atlasTypeToMonioEnum(atlas::array::DataType atlasType) {
   switch (atlasType.kind()) {
-  case atlasType.KIND_INT32: {
-    return consts::eInt;
-  }
-  case atlasType.KIND_REAL32: {
-    return consts::eFloat;
-  }
-  case atlasType.KIND_REAL64: {
-    return consts::eDouble;
-  }
-  default:
-    utils::throwException("utilsatlas::atlasTypeToMonioEnum()> Data type not coded for...");
+    case atlasType.KIND_INT32: {
+      return consts::eInt;
+    }
+    case atlasType.KIND_REAL32: {
+      return consts::eFloat;
+    }
+    case atlasType.KIND_REAL64: {
+      return consts::eDouble;
+    }
+    default: {
+      Monio::get().closeFiles();
+      utils::throwException("utilsatlas::atlasTypeToMonioEnum()> Data type not coded for...");
+    }
   }
 }
 
diff --git a/src/monio/Variable.cc b/src/monio/Variable.cc
index 63501b8..507472c 100644
--- a/src/monio/Variable.cc
+++ b/src/monio/Variable.cc
@@ -15,6 +15,7 @@
 #include "AttributeInt.h"
 #include "AttributeString.h"
 #include "Constants.h"
+#include "Monio.h"
 #include "Utils.h"
 
 monio::Variable::Variable(const std::string name, const int type):
@@ -59,7 +60,8 @@ std::shared_ptr<monio::AttributeBase>
   if (attributes_.find(attrName) != attributes_.end()) {
     return attributes_.at(attrName);
   } else {
-    utils::throwException("Variable::getAttribute()> Attribute \"" +
+    Monio::get().closeFiles();
+utils::throwException("Variable::getAttribute()> Attribute \"" +
                                     attrName + "\" not found...");
   }
 }
@@ -75,11 +77,13 @@ std::string monio::Variable::getStrAttr(const std::string& attrName) {
       value = attrStr->getValue();
       return value;
     } else {
-      utils::throwException("Variable::getAttribute()> "
+      Monio::get().closeFiles();
+utils::throwException("Variable::getAttribute()> "
           "Variable attribute data type not coded for...");
     }
   } else {
-    utils::throwException("Variable::getAttribute()> Attribute \"" +
+    Monio::get().closeFiles();
+utils::throwException("Variable::getAttribute()> Attribute \"" +
                           attrName + "\" not found...");
   }
 }
@@ -91,7 +95,8 @@ void monio::Variable::addDimension(const std::string& dimName, const size_t size
   if (it == dimensions_.end()) {
     dimensions_.push_back(std::make_pair(dimName, size));
   } else {
-    utils::throwException("Variable::addDimension()> Dimension \"" +
+    Monio::get().closeFiles();
+utils::throwException("Variable::addDimension()> Dimension \"" +
                           dimName + "\" already defined...");
   }
 }
@@ -102,7 +107,8 @@ void monio::Variable::addAttribute(std::shared_ptr<monio::AttributeBase> attr) {
   if (it == attributes_.end()) {
     attributes_.insert(std::make_pair(attrName, attr));
   } else {
-    utils::throwException("Variable::addAttribute()> multiple definitions of \"" +
+    Monio::get().closeFiles();
+utils::throwException("Variable::addAttribute()> multiple definitions of \"" +
                           attrName + "\"...");
   }
 }
@@ -122,7 +128,8 @@ void monio::Variable::deleteAttribute(const std::string& attrName) {
   if (it != attributes_.end()) {
     attributes_.erase(attrName);
   } else {
-    utils::throwException("Variable::deleteAttribute()> Attribute \"" +
+    Monio::get().closeFiles();
+utils::throwException("Variable::deleteAttribute()> Attribute \"" +
                           attrName + "\" does not exist...");
   }
 }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 57636e0..0f049d5 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,7 +1,7 @@
 ###############################################################################
 # MONIO - Met Office NetCDF Input Output                                      #
 #                                                                             #
-# (C) Crown Copyright 2023 Met Office                                         #
+# (C) Crown Copyright 2023, Met Office.                                       #
 #                                                                             #
 # This software is licensed under the terms of the Apache Licence Version 2.0 #
 # which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.        #
diff --git a/test/mains/TestFieldSetWrite.cc b/test/mains/TestFieldSetWrite.cc
index fbae32d..30db5f4 100644
--- a/test/mains/TestFieldSetWrite.cc
+++ b/test/mains/TestFieldSetWrite.cc
@@ -11,7 +11,7 @@
 
 /// \brief This test targets Monio::writeFieldSet. An LFRic background file is read, field sets are
 ///        populated, and written directly to file. No comparison takes place as the data are left
-///        in Atlas order. A test pass is achieved simply if the function calls pass without issue.
+///        in Atlas order. A pass is achieved simply if the function calls complete without issue.
 int main(int argc,  char ** argv) {
   oops::Run run(argc, argv);
   monio::test::FieldSetWrite tests;
diff --git a/test/mains/TestStateBasic.cc b/test/mains/TestStateBasic.cc
index 587714e..224ee22 100644
--- a/test/mains/TestStateBasic.cc
+++ b/test/mains/TestStateBasic.cc
@@ -11,7 +11,7 @@
 
 /// \brief This test targets a workflow that avoids the Monio singleton, and the use of Atlas. It
 ///        reads an input file, writes the data to file, reads that back in and checks the data for
-///        integrity. A test pass is achieved if the data first read matches the written data.
+///        integrity. A test pass is achieved if the data first read matches that written.
 int main(int argc,  char ** argv) {
   oops::Run run(argc, argv);
   monio::test::StateBasic tests;