diff --git a/src/db.c b/src/db.c
index e96a43c52..04d94184f 100644
--- a/src/db.c
+++ b/src/db.c
@@ -687,7 +687,7 @@ static void dbSetValue(redisDb *db, robj *key, robj **valref, dictEntryLink link
         }
     }
 
-    if (server.io_threads_num > 1 && old->encoding == OBJ_ENCODING_RAW) {
+    if (server.io_threads_num > 1 && old->encoding == OBJ_ENCODING_RAW && old->refcount == 1) {
         /* In multi-threaded mode, the OBJ_ENCODING_RAW string object usually is
          * allocated in the IO thread, so we defer the free to the IO thread.
          * Besides, we never free a string object in BIO threads, so, even with