diff --git a/cmake/toolchain/heptools-dev-generators.cmake b/cmake/toolchain/heptools-dev-generators.cmake
index fbbc0bd3a6c8e84c984347e8b719f8c720c52927..6e0ffc8cb64fdb5b7dd77268ff4904af3d1a410b 100644
--- a/cmake/toolchain/heptools-dev-generators.cmake
+++ b/cmake/toolchain/heptools-dev-generators.cmake
@@ -147,8 +147,10 @@ LCG_external_package(superchic         3.0          ${MCGENPATH}/superchic    )
 LCG_external_package(superchic         3.03          ${MCGENPATH}/superchic    )
 
 if (NOT (${LCG_OS} STREQUAL ubuntu ))
-LCG_external_package(hoppet              1.1.5          ${MCGENPATH}/hoppet        )
-LCG_external_package(whizard             2.8.0          ${MCGENPATH}/whizard       )
+  LCG_external_package(hoppet              1.1.5          ${MCGENPATH}/hoppet        )
+  if (NOT (${LCG_OS} STREQUAL slc ))
+    LCG_external_package(whizard             2.8.0          ${MCGENPATH}/whizard       )
+  endif()
 endif()
 
 LCG_external_package(hto4l               2.01           ${MCGENPATH}/hto4l         )