diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index b5459b56b..2281c1da0 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -51,12 +51,15 @@ using epee::string_tools::pod_to_hex;
 namespace
 {
 
+#pragma pack(push, 1)
+// This MUST be identical to output_data_t, without the extra rct data at the end
 struct pre_rct_output_data_t
 {
   crypto::public_key pubkey;       //!< the output's public key (for spend verification)
   uint64_t           unlock_time;  //!< the output's unlock time (or height)
   uint64_t           height;       //!< the height of the block which created the output
 };
+#pragma pack(pop)
 
 template <typename T>
 inline void throw0(const T &e)