diff --git a/src/system/game-data.ts b/src/system/game-data.ts
index 161b5a2c49b..c600ba49cb1 100644
--- a/src/system/game-data.ts
+++ b/src/system/game-data.ts
@@ -78,7 +78,7 @@ export function getDataTypeKey(dataType: GameDataType, slotId: integer = 0): str
 export function encrypt(data: string, bypassLogin: boolean): string {
   return (bypassLogin
     ? (data: string) => btoa(data)
-    : (data: string) => AES.encrypt(data, saveKey))(data);
+    : (data: string) => AES.encrypt(data, saveKey))(data) as string;
 }
 
 export function decrypt(data: string, bypassLogin: boolean): string {