diff --git a/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/DatabaseClient.cs b/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/DatabaseClient.cs
index ac6d19c..be5be0a 100644
--- a/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/DatabaseClient.cs
+++ b/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/DatabaseClient.cs
@@ -28,15 +28,10 @@ public DatabaseClient(string username, string password) {
             var docService = new DocumentsService("database");
             docService.RequestFactory = requestFactory;
             
-            //@kims
-            //docService.setUserCredentials(username, password);
             documentService = docService;
              
             var ssService = new SpreadsheetsService("database");
 
-            //@kims
-            //ssService.setUserCredentials(username, password);
-            
             ssService.RequestFactory = requestFactory;
             spreadsheetService = ssService;
         }
@@ -51,26 +46,25 @@ public IDatabase CreateDatabase(string name) {
             }
         }
 
-        public IDatabase GetDatabase(string name) {
-            /*
-            var feed = DocumentService.Query(new SpreadsheetQuery {TitleExact = true, Title = name });
-            if (feed.Entries.Count == 0)
-                return null;
-            return new Database(this, feed.Entries[0]);
-             */
+        /// <summary>
+        /// @kims 2016.08.09. Added second parameter to pass error message by reference.
+        /// </summary>
+        /// <returns>Null, if any error has been occured.</returns>
+        public IDatabase GetDatabase(string name, ref string error) {
+
             Google.GData.Spreadsheets.SpreadsheetQuery query = new Google.GData.Spreadsheets.SpreadsheetQuery();
 
             // Make a request to the API and get all spreadsheets.
             SpreadsheetsService service = spreadsheetService as SpreadsheetsService;
+
             SpreadsheetFeed feed = service.Query(query);
             
             if (feed.Entries.Count == 0)
             {
-                //Debug.Log("There are no spreadsheets in your docs.");
+                error = @"There are no spreadsheets in your docs.";
                 return null;
             }
 
-            //SpreadsheetEntry spreadsheet = null;
             AtomEntry spreadsheet = null;
             foreach (AtomEntry sf in feed.Entries)
             {
@@ -80,7 +74,7 @@ public IDatabase GetDatabase(string name) {
 
             if (spreadsheet == null)
             {
-                //Debug.Log("There is no such spreadsheet with such title in your docs.");
+                error = @"There is no such spreadsheet with such title in your docs.";
                 return null;
             }
 
diff --git a/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/IDatabaseClient.cs b/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/IDatabaseClient.cs
index 17dae7e..d83a313 100644
--- a/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/IDatabaseClient.cs
+++ b/Assets/QuickSheet/GDataPlugin/Editor/GDataDB/GDataDB/IDatabaseClient.cs
@@ -21,6 +21,6 @@ public interface IDatabaseClient {
         /// </summary>
         /// <param name="name"></param>
         /// <returns>IDocument instance or null if not found</returns>
-        IDatabase GetDatabase(string name);
+        IDatabase GetDatabase(string name, ref string error);
     }
 }
\ No newline at end of file
diff --git a/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs b/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
index a262eb9..21f25e1 100644
--- a/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
+++ b/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
@@ -137,8 +137,10 @@ public override void OnInspectorGUI()
 
             if (GUILayout.Button("Generate"))
             {
-                if (Generate(this.machine) == null)
-                    Debug.LogError("Failed to create a script from Google.");
+                if (Generate(this.machine) != null)
+                    Debug.Log("Successfully generated!");
+                else
+                    Debug.LogError("Failed to create a script from Google Spreadsheet.");
             }
         }
 
@@ -162,11 +164,15 @@ private void DoCellQuery(OnEachCell onCell)
             if (string.IsNullOrEmpty(machine.WorkSheetName))
                 return;
 
-            var db = client.GetDatabase(machine.SpreadSheetName);
+            string error = string.Empty;
+            var db = client.GetDatabase(machine.SpreadSheetName, ref error);
             if (db == null)
             {
-                string message = string.Format(@"The given spreadsheet '{0}' or worksheet '{1}' does not exist. Note that the name is case sensitive.",
-                                               machine.SpreadSheetName, machine.WorkSheetName);
+                string message = string.Empty;
+                if (string.IsNullOrEmpty(error))
+                    message = @"Unknown error.";
+                else
+                    message = string.Format(@"{0}", error);
                 EditorUtility.DisplayDialog("Error", message, "OK");
                 return;
             }
@@ -201,6 +207,9 @@ protected override void Import(bool reimport = false)
             else
                 headerDic = machine.HeaderColumnList.ToDictionary(k => k.name);
 
+            List<HeaderColumn> tmpColumnList = new List<HeaderColumn>();
+
+            // query the first columns only.
             DoCellQuery((cell) =>
             {
 
@@ -211,19 +220,29 @@ protected override void Import(bool reimport = false)
                 if (int.Parse(m.Value) > 1)
                     return;
 
-                if (machine.HasHeadColumn() && reimport == false)
+                HeaderColumn column = new HeaderColumn();
+                column.name = cell.Value;
+                if (headerDic != null && headerDic.ContainsKey(cell.Value))
                 {
-                    if (headerDic != null && headerDic.ContainsKey(cell.Value))
-                        machine.HeaderColumnList.Add(new HeaderColumn { name = cell.Value, type = headerDic[cell.Value].type });
+                    // if the column is already exist, copy its name and type from the exist one.
+                    HeaderColumn h = machine.HeaderColumnList.Find(x => x.name == column.name);
+                    if (h != null)
+                    {
+                        column.type = h.type;
+                        column.isArray = h.isArray;
+                    }
                     else
-                        machine.HeaderColumnList.Add(new HeaderColumn { name = cell.Value, type = CellType.Undefined });
+                        column.type = CellType.Undefined;
                 }
                 else
-                {
-                    machine.HeaderColumnList.Add(new HeaderColumn { name = cell.Value, type = CellType.Undefined });
-                }
+                    column.type = CellType.Undefined;
+
+                tmpColumnList.Add(column);
             });
 
+            // update (all of settings are reset when it reimports)
+            machine.HeaderColumnList = tmpColumnList;
+
             EditorUtility.SetDirty(machine);
             AssetDatabase.SaveAssets();
         }
diff --git a/Assets/QuickSheet/GDataPlugin/Templates/ScriptableObjectEditorClass.txt b/Assets/QuickSheet/GDataPlugin/Templates/ScriptableObjectEditorClass.txt
index 61907d8..84c786a 100644
--- a/Assets/QuickSheet/GDataPlugin/Templates/ScriptableObjectEditorClass.txt
+++ b/Assets/QuickSheet/GDataPlugin/Templates/ScriptableObjectEditorClass.txt
@@ -59,7 +59,8 @@ public class $ClassName : BaseGoogleEditor<$WorkSheetClassName>
         $WorkSheetClassName targetData = target as $WorkSheetClassName;
         
         var client = new DatabaseClient("", "");
-        var db = client.GetDatabase(targetData.SheetName) ?? client.CreateDatabase(targetData.SheetName);	
+        string error = string.Empty;
+        var db = client.GetDatabase(targetData.SheetName, ref error);	
         var table = db.GetTable<$DataClassName>(targetData.WorksheetName) ?? db.CreateTable<$DataClassName>(targetData.WorksheetName);
         
         List<$DataClassName> myDataList = new List<$DataClassName>();