diff --git a/helper/resource/error.go b/helper/resource/error.go
index d1f6076f9..7762a2d25 100644
--- a/helper/resource/error.go
+++ b/helper/resource/error.go
@@ -44,10 +44,11 @@ type TimeoutError struct {
 }
 
 func (e *TimeoutError) Error() string {
-	msg := fmt.Sprintf("timeout while waiting for state to become '%s'",
-		strings.Join(e.ExpectedState, ", "))
 	if e.LastError != nil {
-		msg += fmt.Sprintf(". last error: %s", e.LastError)
+		return fmt.Sprintf("timeout while waiting for state to become '%s': %s",
+			strings.Join(e.ExpectedState, ", "), e.LastError)
 	}
-	return msg
+
+	return fmt.Sprintf("timeout while waiting for state to become '%s'",
+		strings.Join(e.ExpectedState, ", "))
 }