diff --git a/accounts/abi/abi.go b/accounts/abi/abi.go
index 535e5d78b..4d29814b2 100644
--- a/accounts/abi/abi.go
+++ b/accounts/abi/abi.go
@@ -82,7 +82,7 @@ func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error) {
 	// we need to decide whether we're calling a method or an event
 	if method, ok := abi.Methods[name]; ok {
 		if len(output)%32 != 0 {
-			return fmt.Errorf("abi: improperly formatted output")
+			return fmt.Errorf("abi: improperly formatted output: %s - Bytes: [%+v]", string(output), output)
 		}
 		return method.Outputs.Unpack(v, output)
 	} else if event, ok := abi.Events[name]; ok {