diff --git a/ApplicationCode/Application/RIApplication.cpp b/ApplicationCode/Application/RIApplication.cpp
index 3232e0f85c..49ae37aba0 100644
--- a/ApplicationCode/Application/RIApplication.cpp
+++ b/ApplicationCode/Application/RIApplication.cpp
@@ -1297,26 +1297,64 @@ void RIApplication::updateRegressionTest(const QString& testRootPath)
 //--------------------------------------------------------------------------------------------------
 /// 
 //--------------------------------------------------------------------------------------------------
-bool RIApplication::addEclipseCase(const QString& fileName)
+bool RIApplication::addEclipseCases(const QStringList& fileNames)
 {
-    QFileInfo gridFileName(fileName);
+    if (fileNames.size() == 0) return true;
 
-    QString caseName = gridFileName.completeBaseName();
-    QString casePath = gridFileName.absolutePath();
 
-    RimResultReservoir* rimResultReservoir = new RimResultReservoir();
-    rimResultReservoir->caseName = caseName;
-    rimResultReservoir->caseFileName = fileName;
-    rimResultReservoir->caseDirectory = casePath;
+    // First file is read completely including grid.
+    // The main grid from the first case is reused directly in for the other cases. 
+    // When reading active cell info, only the total cell count is tested for consistency
+    RigMainGrid* mainGrid = NULL;
 
-    m_project->reservoirs.push_back(rimResultReservoir);
+    {
+        QString firstFileName = fileNames[0];
+        QFileInfo gridFileName(firstFileName);
 
-    rimResultReservoir->openEclipseGridFile();
+        QString caseName = gridFileName.completeBaseName();
+        QString casePath = gridFileName.absolutePath();
 
-    m_project->moveEclipseCaseIntoCaseGroup(rimResultReservoir);
+        RimResultReservoir* rimResultReservoir = new RimResultReservoir();
+        rimResultReservoir->caseName = caseName;
+        rimResultReservoir->caseFileName = firstFileName;
+        rimResultReservoir->caseDirectory = casePath;
+
+        m_project->reservoirs.push_back(rimResultReservoir);
+
+        if (!rimResultReservoir->openEclipseGridFile())
+        {
+            return false;
+        }
+
+        m_project->moveEclipseCaseIntoCaseGroup(rimResultReservoir);
+
+        mainGrid = rimResultReservoir->reservoirData()->mainGrid();
+    }
+
+    for (int i = 1; i < fileNames.size(); i++)
+    {
+        QString fileName = fileNames[i];
+        QFileInfo gridFileName(fileName);
+
+        QString caseName = gridFileName.completeBaseName();
+        QString casePath = gridFileName.absolutePath();
+
+        RimResultReservoir* rimResultReservoir = new RimResultReservoir();
+        rimResultReservoir->caseName = caseName;
+        rimResultReservoir->caseFileName = fileName;
+        rimResultReservoir->caseDirectory = casePath;
+
+        m_project->reservoirs.push_back(rimResultReservoir);
+
+        if (!rimResultReservoir->openAndReadActiveCellData(mainGrid))
+        {
+            return false;
+        }
+
+        m_project->moveEclipseCaseIntoCaseGroup(rimResultReservoir);
+    }
 
     onProjectOpenedOrClosed();
 
     return true;
-
 }
diff --git a/ApplicationCode/Application/RIApplication.h b/ApplicationCode/Application/RIApplication.h
index 6603b52380..4073593ad7 100644
--- a/ApplicationCode/Application/RIApplication.h
+++ b/ApplicationCode/Application/RIApplication.h
@@ -80,7 +80,7 @@ public:
 
     bool                openEclipseCaseFromFile(const QString& fileName);
     bool                openEclipseCase(const QString& caseName, const QString& caseFileName);
-    bool                addEclipseCase(const QString& fileName);
+    bool                addEclipseCases(const QStringList& fileNames);
     bool                openInputEclipseCase(const QString& caseName, const QStringList& caseFileNames);
 
     bool                loadLastUsedProject();
diff --git a/ApplicationCode/FileInterface/RifReaderEclipseOutput.cpp b/ApplicationCode/FileInterface/RifReaderEclipseOutput.cpp
index 4c97977ade..2c88903a4d 100644
--- a/ApplicationCode/FileInterface/RifReaderEclipseOutput.cpp
+++ b/ApplicationCode/FileInterface/RifReaderEclipseOutput.cpp
@@ -430,8 +430,9 @@ bool RifReaderEclipseOutput::openAndReadActiveCellData(const QString& fileName,
     progInfo.setNextProgressIncrement(50);
     progInfo.setProgressDescription("Reading meta data");
 
-    // Build results meta data
-    if (!buildMetaData()) return false;
+    // Reading of metadata and well cells is not performed here
+    //if (!buildMetaData()) return false;
+    // readWellCells();
 
     return true;
 }
diff --git a/ApplicationCode/ProjectDataModel/RimResultReservoir.cpp b/ApplicationCode/ProjectDataModel/RimResultReservoir.cpp
index 5461b8b8f2..6bece89bf8 100644
--- a/ApplicationCode/ProjectDataModel/RimResultReservoir.cpp
+++ b/ApplicationCode/ProjectDataModel/RimResultReservoir.cpp
@@ -90,6 +90,51 @@ bool RimResultReservoir::openEclipseGridFile()
     return true;
  }
 
+//--------------------------------------------------------------------------------------------------
+/// 
+//--------------------------------------------------------------------------------------------------
+bool RimResultReservoir::openAndReadActiveCellData(RigMainGrid* mainGrid)
+{
+    cvf::ref<RifReaderInterface> readerInterface;
+
+    if (caseName().contains("Result Mock Debug Model"))
+    {
+        readerInterface = this->createMockModel(this->caseName());
+
+        m_rigEclipseCase->results(RifReaderInterface::MATRIX_RESULTS)->setReaderInterface(readerInterface.p());
+        m_rigEclipseCase->results(RifReaderInterface::FRACTURE_RESULTS)->setReaderInterface(readerInterface.p());
+    }
+    else
+    {
+        QString fname = createAbsoluteFilenameFromCase(caseName);
+        if (fname.isEmpty())
+        {
+            return false;
+        }
+
+        cvf::ref<RigEclipseCase> eclipseCase = new RigEclipseCase;
+        eclipseCase->setMainGrid(mainGrid);
+
+        readerInterface = new RifReaderEclipseOutput;
+        if (!readerInterface->openAndReadActiveCellData(fname, eclipseCase.p()))
+        {
+            return false;
+        }
+
+        readerInterface->close();
+
+        m_rigEclipseCase = eclipseCase;
+    }
+
+    CVF_ASSERT(m_rigEclipseCase.notNull());
+    CVF_ASSERT(readerInterface.notNull());
+
+    m_rigEclipseCase->computeCachedData();
+
+    return true;
+}
+
+
 
 //--------------------------------------------------------------------------------------------------
 /// 
diff --git a/ApplicationCode/ProjectDataModel/RimResultReservoir.h b/ApplicationCode/ProjectDataModel/RimResultReservoir.h
index cfbffd5abc..31d5f8fe26 100644
--- a/ApplicationCode/ProjectDataModel/RimResultReservoir.h
+++ b/ApplicationCode/ProjectDataModel/RimResultReservoir.h
@@ -24,7 +24,8 @@
 #include "cafPdmObject.h"
 #include "RimReservoir.h"
 
- class RifReaderInterface;
+class RifReaderInterface;
+class RigMainGrid;
 
 //==================================================================================================
 //
@@ -45,6 +46,7 @@ public:
     caf::PdmField<QString>      caseDirectory;
 
     virtual bool                openEclipseGridFile();
+    bool                        openAndReadActiveCellData(RigMainGrid* mainGrid);
 
     //virtual caf::PdmFieldHandle*    userDescriptionField()  { return &caseName;}
 
diff --git a/ApplicationCode/UserInterface/RIMainWindow.cpp b/ApplicationCode/UserInterface/RIMainWindow.cpp
index 407ae81226..9012fca5fc 100644
--- a/ApplicationCode/UserInterface/RIMainWindow.cpp
+++ b/ApplicationCode/UserInterface/RIMainWindow.cpp
@@ -1312,10 +1312,5 @@ void RIMainWindow::slotOpenMultipleCases()
         appendEGRIDFilesRecursively(fileName, gridFileNames);
     }
 
-    for (int i = 0; i < gridFileNames.size(); i++)
-    {
-        QString fileName = gridFileNames[i];
-
-        app->addEclipseCase(fileName);
-    }
+    app->addEclipseCases(gridFileNames);
 }