diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ee90134..0861bc8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -20,11 +20,35 @@ endif ()
 
 #add_dependencies(AnalysisTreeQA ${PROJECT_DEPENDENCIES})
 
-ROOT_GENERATE_DICTIONARY(G__AnalysisTreeQA
-        ${HEADERS}
-        LINKDEF AnalysisTreeQALinkDef.h
-        OPTIONS -I${CMAKE_BINARY_DIR}/include
-        )
+if(${ROOT_VERSION} VERSION_GREATER 6.18.0)
+  message(STATUS "ROOT ${ROOT_VERSION}, use the standard ROOT_GENERATE_DICTIONARY macro.")
+  ROOT_GENERATE_DICTIONARY(G__AnalysisTreeQA
+          ${HEADERS}
+          LINKDEF AnalysisTreeQALinkDef.h
+          OPTIONS -I${CMAKE_BINARY_DIR}/include
+          )
+else()
+  message(STATUS "ROOT ${ROOT_VERSION} has a broken ROOT_GENERATE_DICTIONARY macro, so build the dictionary ourself.")
+  set(dictionary_includes ${HEADERS})
+  set(dictionary_linkdef "AnalysisTreeQALinkDef.h")
+  set(dictionary_source "G__AnalysisTreeQA.cxx")
+
+  add_custom_command(OUTPUT ${dictionary_source}
+                     COMMAND ${ROOT_rootcling_CMD} -f ${dictionary_source}
+                     -rml libAnalysisTreeQA
+                     -rmf libAnalysisTreeQA.rootmap
+                     -s   libAnalysisTreeQA
+                     -inlineInputHeader
+                     -I${AnalysisTree_INCLUDE_DIR}
+                     -I${CMAKE_CURRENT_SOURCE_DIR}
+                     ${dictionary_includes}
+                     ${CMAKE_CURRENT_SOURCE_DIR}/${dictionary_linkdef}
+                     DEPENDS ${dictionary_includes} ${dictionary_linkdef}
+                    )
+endif()
+
+
+
 target_link_libraries(AnalysisTreeQA
         PUBLIC
         AnalysisTreeBase