diff --git a/CLDConfig/CLDReconstruction.py b/CLDConfig/CLDReconstruction.py
index 06583e5..ca2edae 100644
--- a/CLDConfig/CLDReconstruction.py
+++ b/CLDConfig/CLDReconstruction.py
@@ -307,9 +307,12 @@
                                  "UseTruthInPrefit": ["false"]
                                  }
 
-if any(small_vtx in detPath for detPath in geoservice.detectors for small_vtx in ["_o2_", "_o3_", "_o4_"]):
+if len(geoservice.detectors) > 1:
+    raise RuntimeError("Too many XML files for the detector path, please only specify the main file!")
+
+if any(small_vtx in geoservice.detectors[0] for small_vtx in ["_o2_", "_o3_", "_o4_"]):
     CT_MAX_DIST = "0.05;"  # semi-colon is important!
-elif any("_o1_" in detPath for detPath in geoservice.detectors):
+elif "_o1_" in  geoservice.detectors[0]:
     CT_MAX_DIST = "0.03;"  # semi-colon is important!
 else:
     raise RuntimeError("Unknown detector model to chose CT_MAX_DISTANCE")