diff --git a/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationReader.java b/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationReader.java
index 5cb72d1..b8be732 100644
--- a/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationReader.java
+++ b/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationReader.java
@@ -1,6 +1,7 @@
 package pro.litvinovg.w2phtml.gui;
 
 import java.awt.Component;
+import java.io.File;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -8,21 +9,27 @@ import java.util.List;
 import java.util.Set;
 
 import javax.swing.JCheckBox;
+import javax.swing.JFrame;
 import javax.swing.JLabel;
+import javax.swing.JOptionPane;
 import javax.swing.JPanel;
 import javax.swing.JTextField;
 
 import com.sun.star.uno.XComponentContext;
 
-import pro.litvinovg.xml.Debug;
-
 public class ConfigurationReader {
 	
 	HashMap<String,String> options = new HashMap<String,String>();
 	private XComponentContext context;
+	private String format = null;
+	private String inputFilePath = null;
+	private String outputFilePath = null;
+	private String metadataFilePath = null;
+	private JFrame frame;
 
-	public ConfigurationReader(HashMap<String, Component> configuration, XComponentContext context) {
+	public ConfigurationReader(HashMap<String, Component> configuration, XComponentContext context, JFrame frame) {
 		this.context = context;
+		this.frame = frame;
 		readOptions(configuration);
 	}
 
@@ -39,35 +46,19 @@ public class ConfigurationReader {
 				optionValue = ((JLabel) component).getText();
 			}
 			options.put(optionName, optionValue);
-			//Debug.printLog(optionName + " : " + optionValue, context);
 
 		}
-		
-		
+		format = options.get("targetFormat");
+		options.remove("targetFormat");
+		inputFilePath = options.get("inputFile");
+		options.remove("inputFile");
+		outputFilePath = options.get("outputFile");
+		options.remove("outputFile");
+		metadataFilePath = options.get("csv_metadata");
 	}
 
 	public String[] getCommandLine() {
 		List<String> args = new ArrayList<String>();
-		String format = options.get("targetFormat");
-		if (format == null) {
-			Debug.printLog("target format is not set", context);
-			return null;
-		} else {
-			options.remove("targetFormat");
-		}
-		String inputFile = options.get("inputFile");
-		if (inputFile == null) {
-			Debug.printLog("no input file", context);
-			return null;
-		} else {
-			options.remove("inputFile");
-		}
-		String outputFile = options.get("outputFile");
-		if (outputFile == null) {
-			//Debug.printLog("no output file set", context);
-		} else {
-			options.remove("outputFile");
-		}
 		args.add("-"+format);
 		for (String key: options.keySet()) {
 			String value = options.get(key);
@@ -76,17 +67,66 @@ public class ConfigurationReader {
 				args.add(value);
 			}
 		}
-		args.add(inputFile);
-		if (outputFile != null) {
-			args.add(outputFile);
+		args.add(inputFilePath);
+		if (outputFilePath != null) {
+			args.add(outputFilePath);
 		}
 		String sout = "";
 		for (String val: args) {
 			sout += val+" ";;
 		}
-		Debug.printLog(sout, context);
+		//Debug.printLog(sout, context);
 		String[] array = args.toArray(new String[0]);
 		return array; 
 	}
 
+	public boolean isValid() {
+		if (format == null) {
+			return false;
+		}
+		if (inputFilePath == null) {
+			JOptionPane.showMessageDialog(frame, "Input file path is null");
+			return false;
+		}
+		File inputFile = new File(inputFilePath);
+		if (!inputFile.exists()) {
+			JOptionPane.showMessageDialog(frame, "Input file not exists");
+			return false;
+		}
+		if (!inputFile.canRead()){
+			JOptionPane.showMessageDialog(frame, "Input file can not be read");
+			return false;
+		}
+		if (metadataFilePath != null) {
+			File metadataFile = new File(metadataFilePath);
+			if (!metadataFile.exists()) {
+				JOptionPane.showMessageDialog(frame, "Metadata file not exists");
+				return false;
+			}
+			if (!metadataFile.canRead()) {
+				JOptionPane.showMessageDialog(frame, "Metadata file can not be read");
+				return false;
+			}
+		}
+		if (outputFilePath == null) {
+			File inputDir = inputFile.getParentFile();
+			if (!inputDir.canWrite()) {
+				JOptionPane.showMessageDialog(frame, "Output directory is not writable");
+				return false;
+			}
+		} else {
+			File outputFile = new File(outputFilePath);
+			if (!outputFile.canWrite()) {
+				if (outputFile.isDirectory()) {
+					JOptionPane.showMessageDialog(frame, "Output directory is not writable");	
+				} else {
+					JOptionPane.showMessageDialog(frame, "Output file is not writable");
+				}
+				return false;
+			}
+		}
+
+		return true;
+	}
+
 }
diff --git a/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationWindow.java b/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationWindow.java
index 17f4a2c..aba47d4 100644
--- a/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationWindow.java
+++ b/src/main/java/pro/litvinovg/w2phtml/gui/ConfigurationWindow.java
@@ -603,7 +603,7 @@ public class ConfigurationWindow extends JFrame {
 			return;
 		}
 		if (!parent.canWrite()){
-			//TODO: Warning message
+			JOptionPane.showMessageDialog(singleFrame, "Attension. Output file can not be written.");
 		}
 		if (newFilePath.length() < 3) {
 			return;
@@ -891,13 +891,15 @@ public class ConfigurationWindow extends JFrame {
 				JOptionPane.showMessageDialog(singleFrame, "Not implemented, yet.");
 			}
 		});
-		JButton btn_Convert = new JButton("Convert");
-		btn_Convert.addActionListener(new ActionListener() {
+		JButton btn_startConversion = new JButton("Convert");
+		btn_startConversion.addActionListener(new ActionListener() {
 			public void actionPerformed(ActionEvent actionEvent) {
 				try {
-				ConfigurationReader reader = new ConfigurationReader(configuration, context);
-				Application.main(reader.getCommandLine());
-				JOptionPane.showMessageDialog(singleFrame, "Conversion completed.");
+				ConfigurationReader reader = new ConfigurationReader(configuration, context, singleFrame);
+				if (reader.isValid()) {
+					Application.main(reader.getCommandLine());
+					JOptionPane.showMessageDialog(singleFrame, "Conversion completed.");
+				}
 				} catch(Throwable e) {
 					StringWriter errors = new StringWriter();
 					e.printStackTrace(new PrintWriter(errors));
@@ -918,7 +920,7 @@ public class ConfigurationWindow extends JFrame {
 					.addGap(18)
 					.addComponent(btn_Save, GroupLayout.PREFERRED_SIZE, 100, GroupLayout.PREFERRED_SIZE)
 					.addGap(18)
-					.addComponent(btn_Convert, GroupLayout.PREFERRED_SIZE, 100, GroupLayout.PREFERRED_SIZE)
+					.addComponent(btn_startConversion, GroupLayout.PREFERRED_SIZE, 100, GroupLayout.PREFERRED_SIZE)
 					.addContainerGap(427, Short.MAX_VALUE))
 		);
 		gl_panel_control.setVerticalGroup(
@@ -929,7 +931,7 @@ public class ConfigurationWindow extends JFrame {
 						.addComponent(btn_SaveAs)
 						.addComponent(btn_Save)
 						.addComponent(btn_Exit)
-						.addComponent(btn_Convert))
+						.addComponent(btn_startConversion))
 					.addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
 		);