diff --git a/src/borg/crypto/key.py b/src/borg/crypto/key.py
index 8137cfc62..066df18e0 100644
--- a/src/borg/crypto/key.py
+++ b/src/borg/crypto/key.py
@@ -417,6 +417,7 @@ class AESKeyBase(KeyBase):
 
 class FlexiKey:
     FILE_ID = "BORG_KEY"
+    STORAGE = KeyBlobStorage.NO_STORAGE  # override in subclass
 
     @classmethod
     def detect(cls, repository, manifest_data):