diff --git a/app/src/main/java/io/legado/app/help/storage/Backup.kt b/app/src/main/java/io/legado/app/help/storage/Backup.kt
index 462bc445a..3f8e65dd7 100644
--- a/app/src/main/java/io/legado/app/help/storage/Backup.kt
+++ b/app/src/main/java/io/legado/app/help/storage/Backup.kt
@@ -29,7 +29,7 @@ object Backup {
         legadoPath + File.separator + "Export"
     }
 
-    val backupFileNames by lazy {
+    private val backupFileNames by lazy {
         arrayOf(
             "bookshelf.json",
             "bookGroup.json",