diff --git a/server/core/config_runtime.cc b/server/core/config_runtime.cc
index 074c71057..33844b3e2 100644
--- a/server/core/config_runtime.cc
+++ b/server/core/config_runtime.cc
@@ -552,8 +552,9 @@ bool validate_param(const MXS_MODULE_PARAM* basic,
     return rval;
 }
 
-bool do_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value, bool restart_monitor)
+bool do_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value)
 {
+    mxb_assert(monitor->state == MONITOR_STATE_STOPPED);
     const MXS_MODULE* mod = get_module(monitor->module_name, MODULE_MONITOR);
 
     if (!validate_param(config_monitor_params, mod->parameters, key, value))
@@ -568,12 +569,7 @@ bool do_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value,
 
     std::lock_guard<std::mutex> guard(crt_lock);
 
-    if (restart_monitor)
-    {
-        monitor_stop(monitor);
-    }
     monitor_set_parameter(monitor, key, value);
-
     bool success = true;
     if (strcmp(key, CN_USER) == 0)
     {
@@ -654,11 +650,6 @@ bool do_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value,
         mxb_assert(config_param_is_valid(mod->parameters, key, value, NULL));
     }
 
-    if (restart_monitor)
-    {
-        monitor_serialize(monitor);
-        monitor_start(monitor, monitor->parameters);
-    }
     if (success)
     {
         MXS_NOTICE("Updated monitor '%s': %s=%s", monitor->name, key, value);
@@ -668,7 +659,22 @@ bool do_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value,
 
 bool runtime_alter_monitor(MXS_MONITOR* monitor, const char* key, const char* value)
 {
-    return do_alter_monitor(monitor, key, value, true);
+    // If the monitor is already stopped, don't stop/start it.
+    bool was_running = (monitor->state == MONITOR_STATE_RUNNING);
+    if (was_running)
+    {
+        monitor_stop(monitor);
+    }
+    bool success = do_alter_monitor(monitor, key, value);
+    if (success)
+    {
+        monitor_serialize(monitor);
+    }
+    if (was_running)
+    {
+        monitor_start(monitor, monitor->parameters);
+    }
+    return success;
 }
 
 bool runtime_alter_service(Service* service, const char* zKey, const char* zValue)
@@ -2308,7 +2314,7 @@ bool runtime_alter_monitor_from_json(MXS_MONITOR* monitor, json_t* new_json)
                 {
                     /** No change in values */
                 }
-                else if (do_alter_monitor(monitor, key, mxs::json_to_string(value).c_str(), false))
+                else if (do_alter_monitor(monitor, key, mxs::json_to_string(value).c_str()))
                 {
                     changed = true;
                 }