diff --git a/src/main.cpp b/src/main.cpp
index f6a89fa2e6..a8f8e6fa5b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3371,7 +3371,7 @@ static bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state
             if (ppindex)
                 *ppindex = pindex;
             if (pindex->nStatus & BLOCK_FAILED_MASK)
-                return state.Invalid(error("%s: block is marked invalid", __func__), 0, "duplicate");
+                return state.Invalid(error("%s: block %s is marked invalid", __func__, hash.ToString()), 0, "duplicate");
             return true;
         }