diff --git a/core/detectors/sts/CbmStsSetup.cxx b/core/detectors/sts/CbmStsSetup.cxx
index 83d5a4a981f38c6c10ba9777ba59f4fca3c2be91..b075e74585bcb93d12f4dbd223a29949a27af2ba 100644
--- a/core/detectors/sts/CbmStsSetup.cxx
+++ b/core/detectors/sts/CbmStsSetup.cxx
@@ -381,7 +381,7 @@ Bool_t CbmStsSetup::ReadGeometry(TGeoManager* geo)
 
 void CbmStsSetup::RecomputePhysicalAssmbBbox(TGeoManager* geo)
 {
-  TIter nextv(gGeoManager->GetListOfVolumes());
+  TIter nextv(geo->GetListOfVolumes());
   TGeoVolume* vol;
   while ((vol = dynamic_cast<TGeoVolume*>(nextv()))) {
     if (vol->IsAssembly()) vol->GetShape()->ComputeBBox();