diff --git a/src/Extensions/SystemExtensions.cs b/src/Extensions/SystemExtensions.cs
index ee9aa2a..8c2eac0 100644
--- a/src/Extensions/SystemExtensions.cs
+++ b/src/Extensions/SystemExtensions.cs
@@ -21,5 +21,7 @@ public static Exception ShowAndLog(this Exception ex, Logger logger, bool termin
 
             return ex;
         }
+
+        public static string CheckEmpty(this string str) => string.IsNullOrEmpty(str) ? null : str;
     }
 }
diff --git a/src/Forms/SubjectStorageInfoGettingWindow.cs b/src/Forms/SubjectStorageInfoGettingWindow.cs
index 80ba234..b0e8818 100644
--- a/src/Forms/SubjectStorageInfoGettingWindow.cs
+++ b/src/Forms/SubjectStorageInfoGettingWindow.cs
@@ -33,7 +33,7 @@ public SubjectStorageInfo GetResult(SubjectStorageInfo info = null)
 
         private void ButtonGettingPath_Click(object sender, EventArgs e)
         {
-            textBoxPath.Text = FolderBrowserDialogUtilities.GetFilePath();
+            textBoxPath.Text = FolderBrowserDialogUtilities.GetFilePath() ?? textBoxPath.Text;
         }
 
         private void ButtonOK_Click(object sender, EventArgs e)
diff --git a/src/Forms/WindowMain.cs b/src/Forms/WindowMain.cs
index 6873736..1f16c9e 100644
--- a/src/Forms/WindowMain.cs
+++ b/src/Forms/WindowMain.cs
@@ -47,7 +47,7 @@ private void ListViewSubjectStorageInfos_ColumnWidthChanging(object sender, Colu
 
         private void ButtonGettingCoursewareSortingSearchingPath_Click(object sender, EventArgs e)
         {
-            textBoxCoursewareSortingSearchingPath.Text = FolderBrowserDialogUtilities.GetFilePath();
+            textBoxCoursewareSortingSearchingPath.Text = FolderBrowserDialogUtilities.GetFilePath() ?? textBoxCoursewareSortingSearchingPath.Text;
             UpdateSubjectStorageInfoConfig();
         }
 
diff --git a/src/Utilities/FolderBrowserDialogUtilities.cs b/src/Utilities/FolderBrowserDialogUtilities.cs
index 0b89c30..ba8d60e 100644
--- a/src/Utilities/FolderBrowserDialogUtilities.cs
+++ b/src/Utilities/FolderBrowserDialogUtilities.cs
@@ -16,7 +16,7 @@ public static string GetFilePath(string description = "")
             var dialog = new FolderBrowserDialog() { Description = description };
             dialog.ShowDialog();
 
-            return dialog.SelectedPath;
+            return dialog.SelectedPath.CheckEmpty();
         }
     }
 }