diff --git a/MuonSpectrometer/MuonPhaseII/MuonDetDescr/MuonGeoModelTestR4/CMakeLists.txt b/MuonSpectrometer/MuonPhaseII/MuonDetDescr/MuonGeoModelTestR4/CMakeLists.txt
index 9f49652f296d8cdfbe40c68abef675961ce84ede..86c451e82b2c2c37d097d9c9cdcd37052883d890 100644
--- a/MuonSpectrometer/MuonPhaseII/MuonDetDescr/MuonGeoModelTestR4/CMakeLists.txt
+++ b/MuonSpectrometer/MuonPhaseII/MuonDetDescr/MuonGeoModelTestR4/CMakeLists.txt
@@ -6,6 +6,7 @@
 
 # Declare the package name:
 atlas_subdir( MuonGeoModelTestR4 )
+find_package( ROOT COMPONENTS Core Tree TreePlayer )
 
 atlas_add_component( MuonGeoModelTestR4
                      src/components/*.cxx src/*.cxx