diff --git a/pkg/local_object_storage/writecache/init.go b/pkg/local_object_storage/writecache/init.go
index d92e9a2d9..2ca8cceef 100644
--- a/pkg/local_object_storage/writecache/init.go
+++ b/pkg/local_object_storage/writecache/init.go
@@ -86,13 +86,21 @@ func (c *cache) fsTreeFlushMarkUpdate(ctx context.Context) {
 		}
 		return nil
 	}
+
+	c.modeMtx.RLock()
+	defer c.modeMtx.RUnlock()
+
 	_, _ = c.fsTree.Iterate(prm)
+
 	c.log.Info(logs.WritecacheFinishedUpdatingFSTreeFlushMarks)
 }
 
 func (c *cache) dbFlushMarkUpdate(ctx context.Context) {
 	c.log.Info(logs.WritecacheFillingFlushMarksForObjectsInDatabase)
 
+	c.modeMtx.RLock()
+	defer c.modeMtx.RUnlock()
+
 	var m []string
 	var indices []int
 	var lastKey []byte