diff --git a/includes/discovery/os/ios.inc.php b/includes/discovery/os/ios.inc.php
index 731d68bf0..04d399d48 100644
--- a/includes/discovery/os/ios.inc.php
+++ b/includes/discovery/os/ios.inc.php
@@ -22,10 +22,12 @@ if (empty($os)) {
         $os = 'iosxr';
     }
 
-    $extra_mibs = array(
-        "ciscoAAASessionMIB" => "CISCO-AAA-SESSION-MIB",
-    );
-    register_mibs($device, $extra_mibs, "includes/discovery/os/ios.inc.php");
+    if (!empty($os)) {
+        $extra_mibs = array(
+            "ciscoAAASessionMIB" => "CISCO-AAA-SESSION-MIB",
+        );
+        register_mibs($device, $extra_mibs, "includes/discovery/os/ios.inc.php");
+    }
 }
 
 // Fallback case
diff --git a/includes/discovery/os/routeros.inc.php b/includes/discovery/os/routeros.inc.php
index a5e407cd5..4d035a214 100644
--- a/includes/discovery/os/routeros.inc.php
+++ b/includes/discovery/os/routeros.inc.php
@@ -20,8 +20,10 @@ if (!$os) {
     }
 
     // poll Cisco AAA MIB
-    $extra_mibs = array(
-        "ciscoAAASessionMIB" => "CISCO-AAA-SESSION-MIB",
-    );
-    register_mibs($device, $extra_mibs, "includes/discovery/os/routeros.inc.php");
+    if (!empty($os)) {
+        $extra_mibs = array(
+            "ciscoAAASessionMIB" => "CISCO-AAA-SESSION-MIB",
+        );
+        register_mibs($device, $extra_mibs, "includes/discovery/os/routeros.inc.php");
+    }
 }
diff --git a/sql-schema/093.sql b/sql-schema/093.sql
new file mode 100644
index 000000000..6caaecf4e
--- /dev/null
+++ b/sql-schema/093.sql
@@ -0,0 +1 @@
+DELETE FROM `device_mibs` WHERE `module` = 'CISCO-AAA-SESSION-MIB' AND `mib` = 'ciscoAAASessionMIB';