diff --git a/src/login_param.rs b/src/login_param.rs
index e76c1cb53..871ad59b2 100644
--- a/src/login_param.rs
+++ b/src/login_param.rs
@@ -70,6 +70,7 @@ pub struct EnteredImapLoginParam {
     /// Folder to watch.
     ///
     /// If empty, user has not entered anything and it shuold expand to "INBOX" later.
+    #[serde(default)]
     pub folder: String,
 
     /// Socket security.