diff --git a/Core/src/TrackFitting/GlobalChiSquareFitterError.cpp b/Core/src/TrackFitting/GlobalChiSquareFitterError.cpp
index 1f6825d8c81..dff5795c932 100644
--- a/Core/src/TrackFitting/GlobalChiSquareFitterError.cpp
+++ b/Core/src/TrackFitting/GlobalChiSquareFitterError.cpp
@@ -28,6 +28,8 @@ class GlobalChiSquareFitterErrorCategory : public std::error_category {
         return "Gx2f: aMatrix is not invertible.";
       case GlobalChiSquareFitterError::DidNotConverge:
         return "Gx2f: Did not converge in 'nUpdateMax' updates.";
+      case GlobalChiSquareFitterError::NotEnoughMeasurements:
+        return "Gx2f: Not enough measurements.";
       default:
         return "unknown";
     }