diff --git a/solver/processing.go b/solver/processing.go
index d63c4a4..23b771d 100644
--- a/solver/processing.go
+++ b/solver/processing.go
@@ -152,8 +152,9 @@ func (solver *Solver) Tracker() {
 				est, err := time.ParseDuration(duration_string)
 				if err != nil {
 					est_fin = "parse error"
+				} else {
+					est_fin = est.String()
 				}
-				est_fin = est.String()
 			}
 
 			// Printing the progress