diff --git a/src/ai/ai_client.c b/src/ai/ai_client.c
index 320cc98f..32761284 100644
--- a/src/ai/ai_client.c
+++ b/src/ai/ai_client.c
@@ -110,6 +110,7 @@ _aiwin_display_error(gpointer user_data, const gchar* error_msg)
     ProfAiWin* aiwin = _aiwin_validate(user_data);
     if (!aiwin) {
         log_warning("[AI-THREAD] Cannot display error: aiwin is invalid or window was closed (msg: %s)", error_msg);
+        pthread_mutex_unlock(&lock);
         return;
     }
     aiwin_display_error(aiwin, error_msg);