diff --git a/front/maintenance.php b/front/maintenance.php
index 2004bae2..8cd35d63 100644
--- a/front/maintenance.php
+++ b/front/maintenance.php
@@ -41,6 +41,10 @@
           <button type="button" class="btn btn-default pa-btn pa-btn-delete"  style="margin-left:0px;"
             id="btnDeleteMAC"   onclick="askDeleteAllDevices()">   Delete All Devices </button>     
       </div>
+      <div class="center">
+          <button type="button" class="btn btn-default pa-btn pa-btn-delete"  style="margin-left:0px;"
+            id="btnDeleteUnknown"   onclick="askDeleteUnknown()">   Delete (unknown) Devices </button>     
+      </div>
     </div>
 
 
@@ -62,8 +66,7 @@
 // delete devices with emty macs
 
   function askDeleteDevicesWithEmptyMACs () {
-  // Ask delete device 
-
+  // Ask 
   showModalWarning('Delete Devices', 'Are you sure you want to delete all devices with empty MAC addresses?<br>(maybe you prefer to archive it)',
     'Cancel', 'Delete', 'deleteDevicesWithEmptyMACs');
 }
@@ -79,8 +82,7 @@ function deleteDevicesWithEmptyMACs()
 
 // delete all devices 
 function askDeleteAllDevices () {
-  // Ask delete device 
-
+  // Ask 
   showModalWarning('Delete Devices', 'Are you sure you want to delete all devices?',
     'Cancel', 'Delete', 'deleteAllDevices');
 }
@@ -94,8 +96,22 @@ function deleteAllDevices()
   });
 }
 
+// delete all (unknown) devices 
+function askDeleteAllDevices () {
+  // Ask 
+  showModalWarning('Delete (unknown) Devices', 'Are you sure you want to delete all (unknown) devices?',
+    'Cancel', 'Delete', 'deleteUnknownDevices');
+}
 
 
+function deleteUnknownDevices()
+{ 
+  // Execute
+  $.get('php/server/devices.php?action=deleteUnknownDevices', function(msg) {
+    showMessage (msg);
+  });
+}
+
 
 
 </script>
diff --git a/front/php/server/devices.php b/front/php/server/devices.php
index 572da5ef..c6e2f107 100644
--- a/front/php/server/devices.php
+++ b/front/php/server/devices.php
@@ -37,6 +37,7 @@
       case 'deleteAllDevices':        deleteAllDevices();                      break;
       case 'runScan15min':            runScan15min();                          break;
       case 'runScan1min':             runScan1min();                           break;
+      case 'deleteUnknownDevices':    deleteUnknownDevices();                  break;
       
       
  
@@ -200,6 +201,27 @@ function deleteAllWithEmptyMACs() {
   }
 }
 
+//------------------------------------------------------------------------------
+//  Delete all devices with empty MAC addresses
+//------------------------------------------------------------------------------
+function deleteUnknownDevices() {
+  global $db;
+
+  // sql
+  $sql = 'DELETE FROM Devices WHERE dev_Name="(unknown)"';
+  // execute sql
+  $result = $db->query($sql);
+
+  // check result
+  if ($result == TRUE) {
+    echo "Devices deleted successfully";
+  } else {
+    echo "Error deleting devices\n\n$sql \n\n". $db->lastErrorMsg();
+  }
+}
+
+
+
 //------------------------------------------------------------------------------
 //  Delete all devices 
 //------------------------------------------------------------------------------