diff --git a/src/org/ohdsi/rabbitInAHat/RabbitInAHatMain.java b/src/org/ohdsi/rabbitInAHat/RabbitInAHatMain.java
index c4be9ce0..96d658fc 100644
--- a/src/org/ohdsi/rabbitInAHat/RabbitInAHatMain.java
+++ b/src/org/ohdsi/rabbitInAHat/RabbitInAHatMain.java
@@ -46,6 +46,9 @@
 import org.ohdsi.rabbitInAHat.dataModel.Database;
 import org.ohdsi.rabbitInAHat.dataModel.Database.CDMVersion;
 import org.ohdsi.rabbitInAHat.dataModel.ETL;
+import org.ohdsi.rabbitInAHat.dataModel.Field;
+import org.ohdsi.rabbitInAHat.dataModel.MappableItem;
+import org.ohdsi.rabbitInAHat.dataModel.Table;
 import org.ohdsi.whiteRabbit.ObjectExchange;
 
 /**
@@ -77,6 +80,8 @@ public class RabbitInAHatMain implements ResizeListener, ActionListener {
 	private final static FileFilter	FILE_FILTER_DOCX					= new FileNameExtensionFilter("Microsoft Word documents (*.docx)", "docx");
 	private final static FileFilter	FILE_FILTER_CSV						= new FileNameExtensionFilter("Text Files (*.csv)", "csv");
 	private final static FileFilter	FILE_FILTER_R						= new FileNameExtensionFilter("R script (*.r)", "r");
+	private final static FileFilter	FILE_FILTER_XLSX						= new FileNameExtensionFilter("XLSX files (*.xlsx)", "xlsx");
+
 	private JFrame					frame;
 	private JScrollPane				scrollPane1;
 	private JScrollPane				scrollPane2;
@@ -329,6 +334,7 @@ private String choosePath(boolean saveMode, FileFilter... filter) {
 		if (chooser == null) {
 			chooser = new JFileChooser();
 		}
+		chooser.resetChoosableFileFilters();
 		chooser.setFileFilter(filter[0]);
 		for (int i = 1; i < filter.length; i++)
 			chooser.addChoosableFileFilter(filter[i]);
@@ -352,10 +358,6 @@ private String chooseOpenPath(FileFilter... fileFilter) {
 		return choosePath(false, fileFilter);
 	}
 
-	private String chooseOpenPath() {
-		return chooseOpenPath(null);
-	}
-
 	@Override
 	public void actionPerformed(ActionEvent event) {
 		switch (event.getActionCommand()) {
@@ -370,7 +372,7 @@ public void actionPerformed(ActionEvent event) {
 				doOpenSpecs(chooseOpenPath(FILE_FILTER_GZ, FILE_FILTER_JSON));
 				break;
 			case ACTION_CMD_OPEN_SCAN_REPORT:
-				doOpenScanReport(chooseOpenPath());
+				doOpenScanReport(chooseOpenPath(FILE_FILTER_XLSX));
 				break;
 			case ACTION_CMD_GENERATE_ETL_DOCUMENT:
 				doGenerateEtlDoc(chooseSavePath(FILE_FILTER_DOCX));
@@ -521,20 +523,59 @@ private void doOpenSpecs(String filename) {
 
 	private void doOpenScanReport(String filename) {
 		if (filename != null) {
+			boolean replace = true;
+			if (ObjectExchange.etl.getSourceDatabase().getTables().size() != 0){
+				Object[] options = {"Replace current data",
+				"Load data on field values only"};
+				int result = JOptionPane.showOptionDialog(frame, "You already have source data loaded. Do you want to", "Replace source data?", JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, options, options[0]);
+				if (result == -1)
+					return;
+				if (result == 1)
+					replace = false;
+			}
 			frame.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
-			ETL etl = new ETL();
-			try {
-				etl.setSourceDatabase(Database.generateModelFromScanReport(filename));
-				etl.setTargetDatabase(ObjectExchange.etl.getTargetDatabase());
-				tableMappingPanel.setMapping(etl.getTableToTableMapping());
-				ObjectExchange.etl = etl;
-			} catch (Exception e) {
-				e.printStackTrace();
-				JOptionPane.showMessageDialog(null, "Invalid File Format", "Error", JOptionPane.ERROR_MESSAGE);
+			if (replace) {
+				ETL etl = new ETL();
+				try {
+					etl.setSourceDatabase(Database.generateModelFromScanReport(filename));
+					etl.setTargetDatabase(ObjectExchange.etl.getTargetDatabase());
+					tableMappingPanel.setMapping(etl.getTableToTableMapping());
+					ObjectExchange.etl = etl;
+				} catch (Exception e) {
+					e.printStackTrace();
+					JOptionPane.showMessageDialog(null, "Invalid File Format", "Error", JOptionPane.ERROR_MESSAGE);
+				}
+			} else {
+				try {
+					Database newData = Database.generateModelFromScanReport(filename);
+					Database oldData = ObjectExchange.etl.getSourceDatabase();
+					for (Table newTable : newData.getTables()) {
+						Table oldTable = (Table)findByName(newTable.getName(), oldData.getTables());
+						if (oldTable != null) {
+							for (Field newField : newTable.getFields()) {
+								Field oldField = (Field)findByName(newField.getName(), oldTable.getFields());
+								if (oldField != null) {
+									oldField.setValueCounts(newField.getValueCounts());
+								}
+							}
+						}
+					}
+				} catch (Exception e) {
+					e.printStackTrace();
+					JOptionPane.showMessageDialog(null, "Invalid File Format", "Error", JOptionPane.ERROR_MESSAGE);
+				}
+
 			}
 			frame.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
 		}
 	}
+	
+	private MappableItem findByName(String name, List<? extends MappableItem> list) {
+		for (MappableItem item : list)
+			if (item.getName().toLowerCase().equals(name.toLowerCase()))
+				return item;
+		return null;
+	}
 
 	private void doGenerateEtlDoc(String filename) {
 		if (filename != null) {