diff --git a/validat1.cpp b/validat1.cpp
index 3134cbf3..616b92cc 100644
--- a/validat1.cpp
+++ b/validat1.cpp
@@ -449,6 +449,7 @@ public:
 	{
 		if (counter >= outputLen || validOutput[counter] != inByte)
 		{
+			std::cerr << "incorrect output " << counter << ", " << (word16)validOutput[counter] << ", " << (word16)inByte << "\n";
 			fail = true;
 			assert(false);
 		}