diff --git a/src/self_encryptor.rs b/src/self_encryptor.rs
index 80cb7cb11..9ce5c0d32 100644
--- a/src/self_encryptor.rs
+++ b/src/self_encryptor.rs
@@ -575,7 +575,7 @@ where
 async fn decrypt_chunk<S>(
     state: &mut State<S>,
     chunk_number: usize,
-) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, SelfEncryptionError>>>>
+) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, SelfEncryptionError>> + Send>>
 where
     S: Storage + 'static + Send + Sync + Clone,
 {