diff --git a/PowerEditor/src/Notepad_plus.cpp b/PowerEditor/src/Notepad_plus.cpp
index cd957364a..223013f73 100644
--- a/PowerEditor/src/Notepad_plus.cpp
+++ b/PowerEditor/src/Notepad_plus.cpp
@@ -3417,6 +3417,7 @@ void Notepad_plus::command(int id)
 
 		case IDM_SETTING_AUTOCNBCHAR:
 		{
+			const int NB_MIN_CHAR = 1;
 			const int NB_MAX_CHAR = 9;
 
 			ValueDlg valDlg;
@@ -3431,6 +3432,9 @@ void Notepad_plus::command(int id)
 			{
 				if (size > NB_MAX_CHAR)
 					size = NB_MAX_CHAR;
+				else if (size < NB_MIN_CHAR)
+					size = NB_MIN_CHAR;
+				
 				nppGUI._autocFromLen = size;
 			}
 			break;
diff --git a/PowerEditor/src/WinControls/Preference/preference.rc b/PowerEditor/src/WinControls/Preference/preference.rc
index 5e5caa3ee..d77c91e73 100644
--- a/PowerEditor/src/WinControls/Preference/preference.rc
+++ b/PowerEditor/src/WinControls/Preference/preference.rc
@@ -220,4 +220,5 @@ BEGIN
     RTEXT           "From",IDD_AUTOC_STATIC_FROM,208,114,47,8
     CTEXT           "1",IDD_AUTOC_STATIC_N,259,114,8,8
     LTEXT           "th characters",IDD_AUTOC_STATIC_CHAR,273,114,57,8
+	LTEXT           "Valid value : 1 - 9",IDD_AUTOC_STATIC_NOTE,238,124,93,8
 END
diff --git a/PowerEditor/src/WinControls/Preference/preferenceDlg.cpp b/PowerEditor/src/WinControls/Preference/preferenceDlg.cpp
index 5a7dc0720..9d1355b05 100644
--- a/PowerEditor/src/WinControls/Preference/preferenceDlg.cpp
+++ b/PowerEditor/src/WinControls/Preference/preferenceDlg.cpp
@@ -1328,6 +1328,7 @@ BOOL CALLBACK BackupDlg::run_dlgProc(UINT Message, WPARAM wParam, LPARAM lParam)
 				::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_FROM), FALSE);
 				::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_N), FALSE);
 				::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_CHAR), FALSE);
+				::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_NOTE), FALSE);
 			}
 			updateBackupGUI();
 			return TRUE;
@@ -1403,6 +1404,7 @@ BOOL CALLBACK BackupDlg::run_dlgProc(UINT Message, WPARAM wParam, LPARAM lParam)
 					::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_FROM), isEnableAutoC);
 					::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_N), isEnableAutoC);
 					::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_CHAR), isEnableAutoC);
+					::EnableWindow(::GetDlgItem(_hSelf, IDD_AUTOC_STATIC_NOTE), isEnableAutoC);
 					return TRUE;
 				}
 
diff --git a/PowerEditor/src/WinControls/Preference/preference_rc.h b/PowerEditor/src/WinControls/Preference/preference_rc.h
index d26dd1bea..e39b9400f 100644
--- a/PowerEditor/src/WinControls/Preference/preference_rc.h
+++ b/PowerEditor/src/WinControls/Preference/preference_rc.h
@@ -173,3 +173,4 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 	#define IDD_AUTOC_STATIC_FROM  (IDD_PREFERENCE_BACKUP_BOX + 11)
 	#define IDD_AUTOC_STATIC_N  (IDD_PREFERENCE_BACKUP_BOX + 12)
 	#define IDD_AUTOC_STATIC_CHAR  (IDD_PREFERENCE_BACKUP_BOX + 13)
+	#define IDD_AUTOC_STATIC_NOTE  (IDD_PREFERENCE_BACKUP_BOX + 14)