diff --git a/cmake/toolchain/heptools-dev-base.cmake b/cmake/toolchain/heptools-dev-base.cmake
index 9ee0c80a91409687e5b1f584b82ec7695e107136..f9534875cc8f75a2c9ac41eb7a6b76ec1367b614 100644
--- a/cmake/toolchain/heptools-dev-base.cmake
+++ b/cmake/toolchain/heptools-dev-base.cmake
@@ -484,7 +484,9 @@ LCG_external_package(pyparser          1.0
 LCG_external_package(pyparsing         2.4.7                                    )
 LCG_external_package(pyqt5             5.12.3                                   )
 #LCG_external_package(pyqtwebengine     5.12.1                                  )
-LCG_external_package(PyRDF             0.2.1                                    )
+if(NOT ${LCG_COMP} STREQUAL clang)
+  LCG_external_package(PyRDF           0.2.1                                    )
+endif()
 LCG_external_package(pyrsistent        0.18.0                                   )
 LCG_external_package(pyserial          3.4                                      )
 LCG_external_package(pystan            3.1.1                                    )