diff --git a/src/api/api_context.cpp b/src/api/api_context.cpp
index 2b7a4ce43..53f53347e 100644
--- a/src/api/api_context.cpp
+++ b/src/api/api_context.cpp
@@ -157,6 +157,9 @@ namespace api {
         flush_objects();
         for (auto& kv : m_allocated_objects) {
             api::object* val = kv.m_value;
+#ifdef SINGLE_THREAD
+# define m_concurrent_dec_ref false
+#endif
             DEBUG_CODE(if (!m_concurrent_dec_ref) warning_msg("Uncollected memory: %d: %s", kv.m_key, typeid(*val).name()););
             dealloc(val);
         }