Add fingerprints reset on first start

Views/TUIManager.cs

@@ -17,6 +17,7 @@ namespace Akari.Provider.WaveshareUART.Views
         private Label _serialPortLabel;
         private Label _comparisonLevelLabel;
         private Label _userCountLabel;
+        private bool _needToClear;
 
         public TUIManager()
         {
@@ -105,11 +106,23 @@ namespace Akari.Provider.WaveshareUART.Views
             // Init Sensor
             if (!File.Exists(SettingsFilePath))
             {
+                _needToClear = true;
+
                 Application.Run(new SettingsDisplay());
             }
 
             Provider.InitSensor();
 
+            if (_needToClear)
+            {
+                if (!Provider.FingerprintSensor.DeleteAllUsers())
+                {
+                    MessageBox.ErrorQuery("Provider", "Can't clear registered fingerprints, check if the sensor is working correctly", "Ok");
+                }
+
+                _needToClear = false;
+            }
+
             // Update gui
             UpdateSerialPort();
             UpdateUserCount();